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Final article gives the set-up & operating instructions A high-quality DAB+ tuner to build Pt.3: By MAURO GRASSI In this month’s final part, we explain how to use the DAB+/FM Stereo Tuner and describe the menu system. We also show you how you can upgrade the firmware if necessary and describe various features of the tuner in detail. N OW THAT you’ve completed the assembly of the DAB+/FM Stereo Tuner, it’s time to connect it to an amplifier and get it operating. The first thing you’ll need to ensure good reception is an antenna. If you are in a strong reception area, a simple “rabbit ears” antenna may be sufficient to pick up the digital stations but it probably won’t be good enough for FM reception. Instead, we recommend that you use a roof-top TV antenna to ensure good reception of both the digital and FM stations. If you want to listen to both DAB+ and FM stations, it is best to use a dedicated FM antenna. This is because DAB+ can operate at full quality with a much weaker signal than FM. Therefore, even if the FM antenna picks up the DAB+ stations with a fraction of the strength as for FM, it should still provide good digital reception. 78  Silicon Chip If you are mainly interested in tuning in to DAB+ stations, a television antenna is a reasonable choice. This is because DAB+ channels in Australia occupy VHF Band 3 which also contains TV channels 6-12. Of course virtually all Australian television antennas will have elements to pick up channels 7, 9 and 10 and so they should also pick up the DAB stations on either side. The ultimate solution would be to feed the signal from a VHF Band 3 antenna and a dedicated FM antenna into a combiner and then into the tuner. However, unless you are far away from the transmitters, a single antenna should do the job. Navigating the menus Pressing the Menu button brings up the menu system. You can then navigate to a sub-menu either by using the VOL-UP and VOL-DOWN keys on the remote or by using the rotary encoder. Pressing SELECT on the remote or pressing the encoder will then select that menu item. You can also select a sub-menu directly by pressing the number key associated with it. A sub-menu item has square brackets which contain its menu number, whereas a simple menu uses round brackets. Once inside a menu, you can use the encoder to vary the setting up or down, or you can use the VOL-UP and VOL-DOWN on the remote. A menu is exited by pressing the DIMMER (EXIT) button on the remote or the EXIT/MODE pushbutton on the front panel. You can also enter a numeric setting directly, in those menus which take a numeric setting. The display will change as shown in the screengrab of siliconchip.com.au Fig.7 and will give the minimum and maximum allowable settings. As well as changing some of the default values in the menu system, you can also customise the splash screen. When power is applied to the tuner, it initially displays a splash-screen bitmap for a second or so. However, if a memory card with a 160 x 80 monochrome bitmap file called “splash. bmp” (in the root folder) is inserted, this will be displayed instead of the default splash screen. Fig.1: the main menu screen. There are 11 sub-menus to navigate through. Fig.4: the second display mode shows the frequency spectrum amplitudes. Fig.2: a typical readout from the LCD when the tuner is tuned to a station. Fig.5: the third display mode shows an audio level scrolling ramp. Fig.3: the LCD shows the mute status each time the MUTE button is pressed. Fig.6: this display mode shows the radio text in a large font format. Initial set-up The first time you turn the tuner on, the LCD should display the SILICON CHIP logo for about three seconds and then give a warning stating that no digital or FM stations have been programmed in. It should then default to 104.1MHz in FM mode. So the first thing to do is to scan and store the local DAB+ and FM stations. This doesn’t take long and normally only has to be done once, since the results are stored in non-volatile memory. However, if you move house, you will have to re-scan to store the new local stations. Here’s the scanning procedure for the two bands: (1) Scanning For DAB/DAB+ Stations: to do a DAB/DAB+ scan, first enter the menu system by pressing the MENU button. This brings up the main menu, as shown in Fig.1. That done, navigate to the DAB/ DAB+ sub-menu using the UP and DOWN buttons on the remote (or use the rotary encoder), press SELECT (OK) and choose DAB/DAB+ Scan. Check that you have the antenna plugged in, then confirm the operation by pressing SELECT (OK). The scan will take a couple of minutes at most. If all goes well, you will see the stations as they are found. (2) Scanning For FM Stations: there are three choices here – you can perform either a NORMAL or STRONG FM scan, or you can load the FM stations from a file on the memory card. To scan the stations in, go to the menu system and choose the “FM Menu”, then go to the “FM Scan Level” sub-menu and select either a NORMAL or STRONG scan. The difference between the two is the signal strength required for a station to be stored. A STRONG scan will only register stations with good signal strengths while a NORMAL scan will siliconchip.com.au store weaker stations as well. If you want to store all the FM stations in your area, you can load the FM stations from a text file on the memory card. A sample file can be downloaded from the December 2010 section of the SILICON CHIP website and is good for FM stations in Sydney, Australia. You will need to search on-line for the correct frequencies for your city. All you have to do is create a text file with each frequency (in MHz) listed on a separate line (ie, one line per frequency). This file should be named “fm.txt” and placed in the root folder of the memory card. You then insert the memory card into the DAB+/FM Stereo Tuner, switch on and navigate to the FM Menu>Load Stations From File sub-menu. The list of stations will then be read in and stored. LCD overview Fig.2 shows a typical readout from the LCD during normal listening. The top two lines form the “Status Bar” and this shows the volume (or rather, attenuation in -dB) at top left. Alternatively, it will show “Mute” (when the tuner is muted), “Auto” when the muting is controlled automatically, Fig.7: menu settings can be altered using the VOL-UP & VOL-DOWN button on the remote control. or “Static” when the FM Stop Static feature is enabled. The middle of the top line will typically show either “DAB”, “DAB+” or “FM”, depending on the station type. It will also show “ST” or “MONO” to indicate whether the broadcast is stereo or mono. To the right of this, a blinking “IR” indicator will appear when infrared control signals are being received from the remote. In addition, when the “SHIFT” key on the remote is pressed, it will show “SH” (the shift key will time out if no key is pressed within a few seconds). Alternatively, when in FM mode, it will show “IN” (for input) when entering a frequency directly. Finally, the far right of the top line shows the signal level as a percentage. December 2010  79 Setting Up A Universal Remote Control This panel explains how to use a universal remote control rather than the remote control supplied with the DAB+/FM Stereo Tuner kit. This may be necessary if the original remote is lost or becomes faulty. Alternatively, some constructors may prefer to use a universal remote. As previously stated, you must use a universal remote capable of outputting RC5 codes (most do). A suitable remote is the Jaycar AR1726 and this should be set to the VCR 917 code or to some other Philips RC5 code (just follow the instructions supplied with the remote). Other universal remotes will work just as well – just be sure to choose a Philips RC5 code. Start by navigating to the Input Menu on the tuner, then choose the Define Remote Control Codes submenu. You will be prompted to enter a list of keys on the remote. At each stage, you should press the key on the remote that you would like to be the designated function. For example, if you are prompted to “Press Pause”, you should press the key on the remote control that you want to use for the Pause function (ie, mute). At any time, you can press the EXIT/MODE pushbuton on the front panel of the tuner to abort the process. Pressing any other key on the front panel will skip that key’s definition (for example, if your remote does not have enough keys, you can The second line of the status bar indicates the day, date and time. Below this, depending on which of four display modes (see below) is active, the station name, radio text string and other information will be displayed. This “main” area also displays “System Messages”, which indicate that the tuner is responding to commands. tuner has been powered down, as the memory card is detected on start-up. MODE ERROR: this is actually a runtime error, from which the tuner will recover as best it can. It should not happen in normal operation. It can be caused by an unexpected reset of the Venice 7 module. System messages There are four display modes and you can select the next display mode by pressing the DIMMER (EXIT) key on the remote. The first display mode is shown in Fig.2 and this shows the station name in a large font. The next line shows an audio information string, consisting of PTY (Program Type), codec name and the sampling rate and bit rate. A typical string will look like this: “Pop Music, AAC, 48.0 kHz & 96 kbs”. The PTY code is a numeric code transmitted by the station (either from a DAB/DAB+ station or an FM station that transmits RDS). The code gives information about the content being played, in the form of a broad category. Typical codes are “News”, “Pop Music” and “Classical Music” (it gives limited genre information). Codec information: the codec information only applies to digital broadcasts, and will be either “MP2” or “AAC”. “MP2” refers to an MPEG-1 Layer 2 audio codec and is used in DAB broadcasts. “AAC” refers to HE-AAC version When you press the MUTE/PAUSE button on the remote, the LCD will briefly show either “Mute On” or “Mute Off” – see Fig.3. In addition, there are quite a number of other system messages which make the tuner easier to use. These system messages are visible for a short duration only and then the normal display resumes. Here we explain what some of these messages mean (the rest are self explanatory): NO DIGITAL COMPS: you will get this message if you attemp to switch to digital mode but no digital stations are registered. The remedy for this is to perform a DAB/DAB+ scan, as described above. ENTER FREQUENCY: when in FM mode, pressing FF on the remote will allow you to directly enter the station frequency in MHz. CARD EJECTED: this message will appear if a memory card is removed while the tuner is in operation. You should only re-insert the memory card when the 80  Silicon Chip First display mode leave some undefined).You will get a warning saying “Duplicate Key, Try Again!” if you press a key that has already been used for a definition. Once the process completes, the codes are saved to non-volatile memory. Note that the above method can also be used to remap the keys of the supplied remote control, should you wish to do so. However, unless you have a specific reason for doing this, we suggest that you keep the defaults. 2 and is the codec used by DAB+ broadcasts. AAC is more efficient than MP2 and allows better utilisation of the radio spectrum. Sampling and bit rates: these rates apply to digital broadcasts only and are shown in kHz and kbs respectively. They give an indication of the audio quality of the encoding. In general, the higher the numbers the higher the audio quality. Audio level display: the audio level appears below the audio information string and takes the form of a horizontal bar. It varies depending on the RMS value of the audio signal. Radio text display: the radio text information (if any) is shown at the bottom of the display. This is either the DLS (Dynamic Label Segment) for DAB/ DAB+ broadcasts or FM RDS text for FM stations. It will be blank for FM stations that do not transmit RDS. Second display mode The second display mode shows the frequency spectrum amplitudes (as well as maximums for each band, depending on the FFT mode setting in the Preferences sub-menu) – see Fig.4. Below that is shown the station name and system messages, and below that is shown the radio text. Third Display Mode Fig.5 shows the third display mode. This is the same as the second display siliconchip.com.au Start-up Warnings & Troubleshooting The DAB+/FM Stereo Tuner is capable of issuing a number of warnings at start-up. These are as follows: LOW CONTRAST: when the contrast is set too low, there will be a low contrast warning. The contrast is also temporarily set higher to enable this and other warnings to be seen clearly. NO DIGITAL COMPS: this warning indicates that the tuner has no DAB/ DAB+ components (ie, stations). In that case, go to the DAB/DAB+ submenu and perform a scan. Note that if there are no digital components, the tuner will start in FM mode and you will not be able to enter digital mode. NO FM COMPS: this warning indicates that the tuner has no registered FM station frequencies. The unit can still be tuned to any FM station but it’s best to perform an FM scan or load an FM station list from a memory card. Having registered FM components means that the CH UP and CH DOWN functions work faster mode except that instead of showing the frequency spectrum, an audio level scrolling ramp is displayed. Fourth display mode In this display mode, the radio text is shown in its normal inverted scrolling window at the bottom of the display and is also shown in large font in the main area of the display – see Fig.6. This allows the radio text to be read from further away. Below that is shown the station name, along with the audio level display. Status bar As mentioned above, the first line of the “Status Bar” shows the volume and signal strength, plus general information on the tuned station, Below the first line is the date and time, as gathered from the radio signal – either from a DAB+ signal or from an FM RDS signal (if the FM station transmits RDS information). This line will show “Gathering Time . . .” while the tuner is retrieving the time and the time will be synchronised regularly. The period that can elapse before the time is again synchronised is set by the Time>Time Update Period sub-menu. The default period is five minutes. siliconchip.com.au (otherwise the tuner scans for a station each time). DEBUG MODE ON: this indicates that debug mode is enabled. Debug mode should only be used for troubleshooting, as it will affect the responsiveness of the tuner. LOG MODE ON: this warning indicates that logging is enabled. Logging should only be used for troubleshooting as it will affect the responsiveness of the tuner. Run Time Error Reporting The DAB+/FM Stereo Tuner can also issue run-time errors, similar to that shown in the screen grab of Fig.8. These should not occur in normal operation. Any error reports that do occur will indicate the program memory address that caused it. You should note the address and clear the error by pressing SELECT. The errors are listed here and are useful for troubleshooting: However, the time will also be synchronised when the tuner comes out of standby, since the time-keeping is shut down in this mode. That’s because the microcontroller is in sleep mode during this period, so that it draws very little current. The seconds display is optional and can be turned on or off by going to the Time>Time Display sub-menu. General user operation The tuner is easy to operate and can be used either with the supplied remote control or with a universal remote that can transmit RC5 codes. If you elect to use the supplied remote control, there will be no need to program the remote control codes. However, if you are using a universal remote, you will need to program the codes first. This only needs to be done once and the procedure is set out in the panel titled “Setting Up A Universal Remote Control”. The tuner can also be operated using the front-panel controls. There are eight pushbutton switches, a power switch on the far left of the front panel and a rotary encoder with switch action. Almost all functions can be accessed Fig.8: run-time errors are indicated on the LCD but should not occur in normal operation. ADDR. ERROR: an address trap occurred. MATHS ERROR: an ALU trap occurred. STACK ERROR: a stack overflow or underflow occurred. OSC. ERROR: a problem with the microcontroller’s primary oscillator occurred. RADIO NOT DETECTED ERROR: this will be reported when the microcontroller cannot detect the Venice 7 module. All radio functions will then fail to work. Re-install the Venice 7 module and check that it is working correctly if you receive this error. using the front-panel controls. However, some functions and some station presets can only be accessed using the remote control. Normal operation The tuner can operate in either DAB/ DAB+ or FM mode and the interface for each is slightly different. Switching between these two modes is simply a matter of pressing the MODE UP (for DAB/DAB+) or MODE DOWN (for FM) buttons on the remote. Alternatively, you can toggle between the two modes by pressing the “EXIT/MODE” button on the front panel. Once a station is tuned, you can use the VOL-UP and VOL-DOWN keys on the remote control to change the volume, or you can control the volume using the encoder knob on the front panel. The mute/pause button on the remote can be used to “silence” the audio at any time. Sleep & standby modes Pressing the “Sleep” button on the remote (top, centre) switches on the screen saver. When that’s done, the display brightness dims to the level set in the Display>Sleep Brightness submenu. We call this the “Sleep Mode”. December 2010  81 Understanding The Technical Terms Sony/Philips Digital Interconnect Format (S/PDIF): a standard for transferring digital audio data. The standard uses bi-phase encoding and is selfclocking. Inter-IC Sound (I2S): a standard 4-line inter-IC bus for transferring digital audio data. Inter-IC (I2C): a standard 2-line inter-IC serial bus for transferring data at relatively low data rates. It allows many devices to share a common bus and to be individually addressable. Digital Audio Broadcasting (DAB/DAB+): a method for broadcasting digital radio signals, in use around the world. DAB+ is superior to DAB and is the standard used in Australia. DAB and DAB+ are not compatible. A significant difference between them is that the latter uses a more efficient audio codec. Frequency Modulation (FM): a method of encoding audio onto a carrier frequency, where the deviation from the carrier frequency corresponds to the amplitude of the audio. It is more resistant to noise than AM but requires greater spectrum space. Advanced Audio Coding (AAC): a standard lossy audio compression format, used by the Venice 7 module for DAB+ radio reception. MPEG2-Audio Layer 1 (MP2): a standard lossy audio compression format, used by the Venice 7 module for DAB/DAB+ reception. Program Type (PTY): a numeric 5-bit code that contains information about the program currently on the tuned station. It pre-dates DAB/DAB+ and in fact, is used in the FM Radio Data System (RDS). Radio Data System (RDS): a standard for transmitting small amounts of data on top of a standard FM radio signal. It can be used to transmit radio text (song and artist information), station information, program type information and time information, among other uses. Dynamic Label Segment (DLS): a standard way of transmitting small amounts of data on a standard DAB/DAB+ radio transmission. Functions analogously to RDS on FM. Normally, this would be set to a low value (ie, a low percentage of full brightness). In addition, when the time-out period set in the Display>Timeout sub-menu expires (without a key press), the screen saver is invoked automatically. The screen saver shows the time and date, station name and any radio text information. However, if the sleep brightness setting (Display>Sleep Brightness sub-menu) is set to zero, the tuner will go into “Standby Mode” instead. This will occur both when the “Sleep” button is pressed on the remote and at the end of the time-out period. “Standby Mode” is different to “Sleep Mode”. While the latter simply invokes a screen saver, the microcontroller will still be fully operational. On the other hand, in “Standby Mode”, the microcontroller enters low-power mode and is essentially shut down except for minimal functions. In this mode, the display switches off but the 82  Silicon Chip radio keeps operating. During “Standby Mode”, the blue indicator LED (LED3) flashes periodically (provided the LED brightness, as set in the Display>LED Brightness sub-menu, is not set to zero). You can press the red “Standby” button on the remote to place the tuner in standby mode at any time too. Pressing any key on the remote or on the front panel switches the tuner back out of standby or sleep mode. Storing & using presets You can store up to 10 preset stations for DAB/DAB+ mode and 10 for FM mode. Once these have been stored, pressing a digit from 1-10 on the remote loads the corresponding preset station, depending on the mode. Alternatively, you can access the first six presets for either mode using the 1-6 front-panel switches. If a preset has not been set for a particular button, you will get a “Preset Empty” message on the display. To store a preset, first tune to the station that you want to store, then press “SCAN” on the remote followed by the digit number for the preset. The tuned station will then be stored as a preset. This procedure works in both DAB/DAB+ and FM modes. Note: the “SCAN” key acts like a shift key. Pressing and holding this down before pressing another key enables an additional function. At any time, you can use the “MENU” button to enter the menu system. The accompanying panel titled “Navigating & Using The Menu System” describes the menu system in detail and details how the settings are changed. Changing stations Once the stations have been scanned and stored, you can press the “CH-UP” and “CH-DOWN” buttons to change to the next or previous station. The digital stations are sorted alphabetically by name, while the FM stations are sorted by frequency from the lowest to the highest. Pressing the “SELECT” button on the remote brings up a list of stations on the LCD. You can then select a station by scrolling up or down the list using the VOL-UP & VOL-DOWN or CH-UP & CH-DOWN keys on the remote and pressing the SELECT button. Alternatively, pressing the DIMMER (EXIT) button on the remote control will abort the selection. You can also change stations by pressing the encoder knob and then using the encoder to scroll up or down the list. Pressing the encoder knob again then selects the highlighted station. In FM mode, you can also press the FF button on the remote and enter in the station frequency directly using the numeric keys on the remote. You then press the FF button again to tune to the entered frequency. For example, if you are in FM mode, you can press FF, 1, 0, 2, 5, FF to tune to 102.5MHz. Playing back WAV files In order to play back uncompressed WAV files from the memory card, you must first store the files on the memory card with a “.wav” extension. You then insert the memory card into its slot (on the front panel) while the tuner is powered off (note: you should always insert the memory card when the power is off, as the memory card siliconchip.com.au Upgrading the Firmware Fig.9: the firmware in the tuner’s microcontroller can be upgraded by running the dabt.exe utility (see text). The DAB+/FM Stereo Tuner incorporates a bootloader program (in microcontroller IC1) which allows its firmware to be updated via the serial port. This is done using a PC and the supplied program dabtb.exe (available on the SILICON CHIP website). To upgrade the firmware, you will need the new firmware image (this is a .hex file), the dabtb.exe executable, a serial cable and a Windows-based PC with a serial port. It is important that power is maintained during the firmware update. If power is accidentally lost, you will have to start the update procedure all over again from step 1 (see below). Before proceeding, note that all stored settings (apart from the defaults) will be lost after a firmware upgrade. This will include any station presets and remote control codes. The way around this is to save all your stored settings to a file on a memory card, then restore them later on. Automatic update The easiest way to update the firmware is to use the automatic option. The step-by-step procedure is as follows: (1) Save your existing settings to a file on the memory card. This is done by navigating to the System>Save Settings To File sub-menu). (2) Connect the tuner to a Windowsbased PC using a serial cable. If your PC doesn’t have a serial port, you can use a USB-Serial converter, such as siliconchip.com.au Fig.10: you can check your PC’s COM port number via Device Manager. In this case, a USB-serial converter is being used. the Jaycar XC-4834 (most notebooks lack a serial port). (3) Boot the PC and download the dabtb.exe program from the SILICON CHIP website. (4) Start the bootloader by applying power to the tuner while holding down the MENU button on the front panel. Alternatively, the bootloader can be entered through the menu system (Advanced>Boot Loader). Note that if you press the “EXIT/MODE” button on the front panel while the boot loader is active, you will exit the boot loader (this will not work if the program memory has been erased). (5) Once the bootloader has started, the LCD will be blank (with its backlight off) and the blue LED on the front panel will flash periodically. This means that the tuner is in bootloader mode and is ready to receive commands from the PC through the serial port. (6) Run the dabtb.exe application on the PC. This will bring up a dialog window as shown in Fig.9 but with the text area initially blank. It has a number of buttons and a LINK check box which is green when there is a connection (it’s red otherwise). (7) You must know which COM port you are using to connect to the tuner. If you are using a native COM port (usually only desktop PCs will have one), it will be either COM1 or COM2. Alternatively, if you are using a USBserial converter, the COM port number could be different. You can check the PC’s COM port number by going to “Control Panel” and then to “Device Manager”. This will show the hardware installed on your system. The COM port number will be listed under “Ports (COM & LPT)”, as shown in the screen grab of Fig.10. In this particular case, the relevant port is the “Prolific USB-to-serial Comm Port (COM4)”, which indicates that we should use COM4. (8) Once you have determined the correct COM port number, select the correct number from the drop-down list (COM ports from COM1 to COM16 can be chosen), then click the “Connect” button. If all is well, you will get a “Connecting to COM4: Ok.” message in the text box. If you don’t get this message, you may have the wrong COM port selected or the driver for your USB-serial converter (if you are using one) may not be installed correctly. (9) Press the “Program” button to start reprogramming the firmware. If all goes well, you will be asked to browse for a hex file and then, after a few minutes, the process should end without errors. The tuner should now boot into the new firmware version the next time it is powered up. You can check that the firmware has indeed been updated by going to the System>Firmware Information submenu. (10) Restore your settings from the previously-saved memory card file by going to the System>Restore Settings From File sub-menu. December 2010  83 Navigating & Using The Menu System This section describes the menu system and the various settings in detail. The menu system will need to be used only rarely, as the settings are stored in non-volatile memory and the defaults will be suitable for most users. Each menu consists of a number of entries and each entry can be a menu or a sub-menu. The menus are as follows: DAB/DAB+ Menu DAB/DAB+ Scan: used to scan digital radio stations. You must confirm the scan by pressing OK. Pressing any other key or letting the confirm menu time out will abort the scan. If you confirm the scan, the tuner will immediately begin scanning for stations. This can take up to two minutes to complete and the stations detected are stored in non-volatile memory. You must perform a scan at least once before using the tuner and you will need to repeat the procedure if you move to a different city or suburb. Regular scans will ensure that your station list is up to date. DAB/DAB+ Band: enter this menu to select the DAB/DAB+ band of operation for the tuner (note: the tuner is capable of working on three separate frequency bands). In Australia, Band 2 (87.5-108MHz) is used for FM broadcasts, while VHF Band 3 (174-230MHz) is used for digital radio. The default setting of “Australia/ Europe” enables both Band 3 and Lband for DAB/DAB+ and is correct for Australia. Other possible settings are: Korea: use this setting for Korea; Canada: use this setting for Canada; UK: use this setting for the UK; Band 3: VHF Band 3 reception only; L-Band: UHF L-band reception only. Station List: this shows the station list for DAB/DAB+. The list is updated every time you perform a DAB/DAB+ scan. Each station’s name is shown and you can press the VOL-DOWN key to scroll down the list. Press EXIT (DIMMER) to exit the station list. Frequency List: this shows the list of DAB/DAB+ frequencies in MHz. You must perform a scan before this list is updated. Press the VOL-DOWN key 84  Silicon Chip to scroll down the list and press EXIT to exit the frequency list. Restore Defaults: you will be asked to confirm this action. If you do, the default DAB/DAB+ menu settings are restored. FM Menu FM Scan: enter this menu to scan in FM stations.You must confirm the scan by pressing OK. Pressing any other key, or letting the confirm menu time out, will abort the scan. If the scan is confirmed, the tuner will search for FM stations. Two types of scan can be performed, a STRONG or NORMAL scan. The STRONG scan will only pick up stations that have a strong signal, whereas the normal scan will pick up all stations, even those that have a weak signal. Selecting a STRONG or NORMAL scan is done in the FM Scan Level sub-menu. The whole scan can take a couple of minutes and the detected stations are stored in non-volatile memory.You should perform a scan at least once before using the tuner and, as before, you must perform a scan if you move to a different area or suburb. Note that for FM, it is not necessary to perform a scan if you have a list of the station frequencies in your area. In that case, you can use the Load Stations from File sub-menu to load the stations directly. This option is recommended if you are in a weak signal area or in an area where there are many weak stations. FM Scan Level: this menu lets you change the scan mode to either STRONG or NORMAL. As explained above, this affects the threshold for locking onto an FM station, during an FM scan. If you are in a weak signal area, you would specify NORMAL, otherwise specify STRONG to store only strong-signal stations. Load Stations From File: use this menu to load a list of FM stations from a text file called “fm.txt” in the root folder of a memory card. The tuner will read this file and update the station list. A sample file for Sydney, Australia can be downloaded from the SILICON CHIP website. Each frequency should be on a separate line (with hard carriage returns). Stop Static: if enabled, this will automatically mute static (noise) in FM mode. Station List: this shows the list of FM stations (ie, frequencies). You must perform an FM scan or load the station list from a file before this list is updated. The frequencies for FM reception are shown in MHz. Press the VOL-DOWN key to scroll down the list and press EXIT to exit this menu. Restore Defaults: you will be asked to confirm the action. If you do, the default FM menu settings are restored. System Menu This menu can be used to save and restore settings to the memory card. It can also provide useful information for troubleshooting. Firmware Information: this menu shows the firmware version and the Venice 7 firmware version. This is useful for troubleshooting. Save Settings To File: use this menu to save all settings to a file on the memory card. This also saves any remote control codes which have been defined.You should do this once you are happy with your settings. The file can then be used in the future to restore your settings, if necessary. The file is saved to “setYYYYMMMDDhhmmss.bin”, where YYYY is the year, MM is the month, DD is the day, hh is the hour, mm is the minutes and ss is the seconds (ie, the date and time when the file was saved). You will need to confirm the action. Restore Settings From File: use this menu to restore all settings, including any custom remote control codes, to those previously saved in a “*.bin” file using the menu above. You will need to confirm the action. Display Menu This menu controls all settings to do with the LCD and LED3 on the front panel. Brightness: use this menu to set the brightness of the LCD module’s LED backlighting. The setting is a percentage of full brightness. Contrast: allows you to set the contrast of the LCD module. The setting is a percentage. Timeout: this controls the duration of siliconchip.com.au the timeout period. If no key presses are detected for the duration of this period, the tuner will go to “sleep”. In this mode, the display will dim and show the time. The tuner can then be woken again up by pressing any key. The default timeout value is 10 minutes but can be set anywhere between one second and nine hours. A value of “0” disables the timeout. Sleep Brightness: this is a percentage that sets the brightness of the LCD module’s LED backlighting when the unit is in “sleep” mode LED Brightness: this controls the brightness of LED3 on the front panel. Restore Defaults: use this menu to restore all display menu settings to their default values. Audio Menu This menu is used to change the audio settings, as follows: Audio Fading: you can enable or disable audio fading. When enabled, the audio will fade in from maximum attenuation to the set volume when a new station is tuned. Use Hardware Mute: enable this to only use the hardware mute circuit for muting the tuner, rather than a software mute. The default is software muting. Audio DRC (Dynamic Range Control): used to vary the dynamic range compression. It allows you to change the compression applied to the DAB/ DAB+ audio stream. The possible settings are NONE, HALF, FULL and TWICE. The default setting is FULL which applies the recommended amount of DRC embedded within the broadcast data. You can choose to turn off DRC altogether by selecting NONE, or use only half (HALF) DRC. Alternatively, you can double the normal level of DRC (TWICE). Input Menu This menu can be used to check that the input devices are all working. Check Keys: use this menu to check that the tuner correctly recognises remote control signals and correctly decodes the front panel pushbuttons. The key code is displayed on the first line (“Key”), along with the translated code (“Tr. Key”). The number of bits and protocol of the IR signal is also shown. The DAB+/FM Stereo Tuner can siliconchip.com.au recognise both 12-bit RC5 codes from a universal remote and 32-bit codes from the supplied remote control. If checking the front panel pushbuttons, that will be indicated too. Check Encoder: used to check that the rotary encoder on the front panel PC board is working correctly. The display should change according to whether the rotary encoder is turned clockwise or anticlockwise. Key Repeat Period: changes the time period between repeated key presses. The setting is shown in milliseconds. Define Remote Control Codes: use this menu to define the remote control codes if you are using a universal RC5 remote control. You will need to follow the on-screen prompts. Pressing a pushbutton on the front-panel PC board will skip the key (if you press EXIT/MODE on the front panel, you can abort the process altogether). Note that you will only need to do this if you wish to use a different remote control to the one provided with the kit (see panel). Check Serial Port: use this menu to check that serial port communications between your PC and the tuner are working correctly. The tuner will echo back any received character and display it on the screen. You can use a terminal program for your PC such as realterm.exe (Real Terminal, freely downloadable from sourceforge.net). The tuner’s serial port is configured for 115,200bps, 8 bits, 1 stop bit and no parity. Preferences Menu This menu changes the way text appears on the LCD. The default settings should be suitable for most people but you can also customise them to suit your own preferences. Radio Text Delay: sets the scroll rate for the DLS (dynamic label segment) or FM RDS (radio data service) information string. The higher the delay, the slower it scrolls Radio Text Shift: typically, this should be set to “1” for smooth scrolling. Increase this number to shift in blocks of more than one column. If you are going to increase this setting, you would normally also increase the Radio Text Delay setting to avoid the text changing too rapidly. Station Name Mode: there are three options here, as follows: (1) No Scrolling: in this mode, the station names are shown without scrolling. That is, if the name of the digital station is too long to fit on the display, the font is reduced to make it fit. This is the default option. (2) Scrolling: in this mode, the station names are shown in the largest font at all times. If the name is too big to fit inside the window, it is scrolled. (3) Short Names: in this mode, the station names are shown in the largest font at all times. Only the short name of the digital station is shown (which is an abbreviation of the full name). Window Delay: the higher the delay, the slower the windows containing the station name and audio information will scroll. The default setting should be suitable in most cases. Window Mode: there are two options here: (1) Normal: the middle windows are shown normally, with the text composed of white pixels on a blue background. The status bar and radio text display areas are inverted. (2) Inverter: the middle windows are inverted from the NORMAL setting. This is good for extra contrast. FFT Mode: there are four options here: (1) Left & Maximums: spectrum is left justified, with lower frequencies to the left. Maximum indicators are shown. (2) Centre & Maximums: spectrum is symmetrical about the centre. Maximum indicators are shown. (3) Left No Maximums: spectrum is left justified, with lower frequencies to the left. No maximum indicators are shown. (4) Centre No Maximums: spectrum is symmetrical about the centre. No maximum indicators are shown. Restore Defaults: used to restore the default preference menu settings. Time Menu Time Display: there are two options here: (1) Basic Time: in this mode, the weekday, date (including day, month & year) and the time in hours and minutes (24-hour format) are shown. (2) Show Seconds: the same as Basic Time mode but with seconds also shown. Time Update Period: this is the time that elapses before the tuner’s clock is re-synchronised to the time signal received from either a DAB/DAB+ . . . continued next page December 2010  85 Navigating & Using The Menu System . . . ctd signal or FM RDS time data. Note that not all FM stations transmit RDS information, so the time may not be accurate if tuned to an FM station that does not transmit RDS. The time display will change to “Gathering Time . . .” while the tuner is synchronising the time with the broadcast signal. Advanced Menu This menu will rarely need to be used, if at all. It’s there for troubleshooting purposes or for upgrading the firmware in the microcontroller. Firmware Information: this menu shows the microcontroller firmware version and the Venice 7 module firmware version. Debug Mode: this is useful for troubleshooting. Debug mode can be used to see the packets between the microcontroller and the Venice 7 module using the serial port and a terminal emulator. The possible settings are: (1) On: this should only be enabled for troubleshooting, as it will slow down the responsiveness of the tuner to commands. detection occurs on start up). Pressing the INFO button on the remote (“Play”) starts playback of the uncompressed WAV files on the memory card. This also brings up a menu on the LCD which shows the directory structure of the memory card. Only files with a “.wav” extension will be displayed. If the WAV file contains metadata information specifying the song title, this will be displayed, otherwise the filename itself is displayed. You can select a file by pressing SELECT on the remote control or by using the rotary encoder on the front panel. Note that you can use freeware such as Audacity (http://audacity.sourceforge.net) to convert your music to WAV format. You can also use Audacity to resample a track or to add artist and title information that the tuner will recognise. Automatic muting Another feature of the tuner is automatic muting. This takes place 86  Silicon Chip (2) Off: in normal operation, select Off to disable debug mode. Bridge Mode: used to enable or disable bridge mode. Bridge mode can be used to troubleshoot any problems with the Venice 7 module itself In this mode, the microcontroller acts as a relay between the serial port and the Venice 7 module, meaning the Venice 7 module can be controlled directly from a PC through a serial connection. This mode is not used at consumer level. Boot Loader: used to enter the boot loader to allow firmware upgrades to the microcontroller (should upgrades become available). The procedure is described in a separate panel titled “Upgrading the Firmware DAB+/FM Stereo Tuner”. Radio Factory Reset: restores the factory defaults for the Venice 7 module. This will delete all stored DAB/DAB+ stations, so a rescan will be required. Restore Radio Defaults: use this submenu to restore all the tuner’s default settings. It will not delete stored DAB/ DAB+ stations from memory, though. Reset: restarts the tuner. when changing stations in both digital and FM modes. Basically, the audio is muted until the microcontroller detects a signal on the output of the Venice 7 module (this is done using the I2S connection from the Venice 7 module). When a signal is detected, the muting is automatically switched off. Note that the volume display on the LCD shows “Auto” while ever the automatic muting is enabled. The automatic muting can be disabled by pressing the MUTE button (top left) on the remote. FM “stop-static” feature Enabling the “Stop Static” feature (FM>Stop Static sub-menu) allows the automatic muting to cut in if static is detected in FM mode. When this happens, the audio is muted while ever the noise remains. The following conditions must be met for the audio to remain muted: (1). The signal must be so weak that the station is received in MONO (if a stereo FM signal is received, the mut- Memory Card Menu Memory Card Information: this menu is used to display information about the memory card. This includes its serial number, the type of card (ie, MMC, SD or SDHC), its name, capacity and free space, etc. Eject Memory Card: lets you remove the memory card without losing information. All logging writes are finalised, after which the card can be removed. Logging Menu This menu allows you to enable logging to the memory card and can be useful for troubleshooting purposes. It will rarely need to be used, if ever. Log Mode: used to enable logging. There are two options: (1) Off: all logging is disabled. (2) System: only system events are logged. Log Session Size: this sub-menu lets you set the maximum size of the log file on the memory card. If the limit is reached, subsequent log requests will be ignored. Note that the log file is cleared at boot time. Show Log: used to view the log file. Errata DAB+/FM Stereo Tuner, Pt.1, Oct­ ober 2010: the LM317T regulator on the main circuit (Fig.1, p.27) should be designated REG4, while the LM3940 immediately above it should be designated as REG5. The parts layout diagram in Pt.2 (Fig.3, p.71, November 2010) is correct. ing will not work); and (2). The microcontroller (which monitors the I2S bus) determines that the signal contains static due to its relatively constant level. The volume display will show “Static” while ever this feature is active. However, static detection is not foolproof and can be manually overridden if necessary using the MUTE button on the remote. Alternatively, it can be disabled altogether via the FM sub-menu. Finally, note that a complete kit of parts for this project is available from Jaycar Electronics, Cat. KC5491. SC siliconchip.com.au