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Introducing the SPLat CC16 . . . the world’s lowest cost “industry-ready” OEM controller! By PETER SMITH SPLat Controls, an Australian company that produces a range of home-grown industrialstrength controllers, recently added the credit-card sized ‘CC16’ to their line-up. This new controller sells for less than $100 yet includes many of the features of SPLat’s more sophisticated controllers. T HE CC16 BOASTS 16 digital input/output (I/O) lines. All inputs feature over-voltage protection and are designed to work with industrial style “NPN” type sensors. The outputs are capable of sinking up to 400mA and can directly drive solenoids, contactors and small stepper motors – so for many applications, no additional interfacing circuits are required. Like all SPLat controllers, the CC16 utilises a proprietary programming 22  Silicon Chip language. Unlike other controllers that use C, BASIC or ladder logic, the SPLat language was designed from the ground up for industrial control and is therefore exceptionally easy to use. While it is possible to create rudimentary programs in minutes using a subset of the SPLat language called “Fast-track”, much more sophisticated control functions can also be built that include maths, state machines, heuristics and look-up tables. A major selling point of the controller is its multi-tasking abilities, which are an integral part of the SPLat language. Up to 32 concurrent tasks coupled with an execution rate of about 15,000 high-level SPLat instructions per second provide enough scope for a wide variety of applications. Add to that the large program memory (approx. 12,000 instructions) and it’s hard to imagine a job that these little devices couldn’t tackle! SPLat’s claim that their programming language is the “easiest in the world” for embedded OEM applications piqued our curiosity. While it might be easy for an experienced programmer to use, how would someone with no programming experience fare? To learn more, we obtained a CC16DK Developer’s Kit which includes the CC16 controller, a CD-ROM with PC software and technical information, a siliconchip.com.au Fig.1: the CC16 features 16 digital input/ output (I/O) lines. Here’s the basic structure of a single I/O line, showing how one input and one output are connected together and brought out to a single point. Each output is capable of sinking up to 400mA, made possible by ULN2803A high-voltage Darlington driver ICs. When used as inputs, 330kW resistors divide the applied voltage by two. The 330kW series resistor also limits current flow in the micro’s internal protection diodes to provide overvoltage protection. A logic low is specified as 0-3V on an input and a logic high as 7-32V. For those interested, the complete schematic can be downloaded from www.splatco.com.au – look in “Outline drawings & other files” under the “Support” section. serial cable and five friction lock connectors for I/O and power hook-up. A power supply is not included in the kit but a plugpack or any DC supply that can provide 10-24V will work. Getting started The first step is to install the Windows-based development software, “SPLat/PC”. While we installed ours from the CD, it is also available for free download from www.splatco.com. au. The software provides a means of entering and testing your SPLat programs and includes a comprehensive help system. The serial cable mentioned earlier connects the CC16 to a free serial port on your PC, allowing SPLat/PC to communicate with the controller for debugging and programming. USB-to-serial adapters are available separately if your system lacks the necessary port. Once testing is complete, a couple of keystrokes see a “tokenised” version of your program uploaded to the flashbased memory in the CC16’s on-board microcontroller. The controller is then ready for use and can be disconnected from the PC. Note: for the technically curious, the microcontroller embedded in all SPLat controllers is factory programmed with run-time firmware that interprets and executes your tokenised program. This means that your program is not compiled to machine code; rather, it is converted to a “shorthand” language (and all comments stripped away) to conserve space in the micro’s Flash memory. SPLat provide free updates to the on-board firmware as new features siliconchip.com.au are implemented. A simple system called “reFlash” is used to apply the updates to all later model controllers, including the CC16. When SPLat/PC is first launched, a message appears encouraging you to follow a “mini-tutorial”. This tutorial describes the basics of the system and gives a rudimentary, hands-on programming example. Let’s look at a few of the simple examples given in the tutorial to get an idea of how the SPLat programming system works. Programming The Editor window opens immediately when SPLat/PC is started (see Fig.2). This window functions as a basic text editor, where you enter and edit your SPLat program. It also acts as the central control point for all other functions. From within this window, you can write your programs, test them and then download them to the CC16 controller. The program shown in Fig.2 makes use of SPLat’s simplified Fast-track instruction subset. It waits for input 0 to turn on (go to a logic “low” level) and then turns on output 5. It then waits for input 0 to turn off (go high) again before turning output 5 off and then looping back to the start. Having entered this simple program, we can then download it directly to the controller and check if it works as intended. However, unlike this ridiculously simple example, most real programs will have a few problems and will not operate as expected without “debugging”. This is where the real power of SPLat’s development environment comes in. We can step through our program one line at a time, get it to stop at any line we desire or run it uninterrupted to help track down any anomalies (Fig.3). To see the state of the outputs, it’s just a matter of opening the Input/ Output window from the toolbar (Fig.4). This window (Fig.5) gives a graphical representation of the state of each output line in the form of a graphical “LED”. The Input/Output window also includes a graphical “switch” for each input line, allowing the state of any input to be viewed and altered with just a mouse click – so it’s easy to simulate a real switch on any of the controller’s input lines. This enables you to test and debug your program without even having the real-word sensors or switches wired to the controller! Fig.2: SPLat/PC’s Editor window looks a lot like Windows Notepad and works in a similar fashion. Here we’ve typed in a very simple program (borrowed from the mini-tutorial) using just a few instructions from the Fast-Track instruction subset. The operation of the program is largely selfexplanatory (see text). April 2007  23 Fig.3: once you’ve entered your program, you can use the debugging functions on the Run menu to pause execution at a particular line or to step through one line at a time. This makes it much easier to track down bugs and is invaluable as a training aid. Fig.4: a whole host of other windowed functions can be opened from the Editor’s Window menu to assist in the development and debugging of a program. In this short review, we mention only the “Input/ Output” window (see Fig.5). A 64-pin MC9S08AW60 surface-mounted microcontroller IC (the small square black device) accounts for the vast majority of the CC16’s operation. All connections to the board are made via friction lock connectors on a 2.54mm pitch. The four 6-way connectors on the left side each carry four I/O lines, power and ground. The 3, 4 and 8-way connectors at the right and bottom sides provide for power input, serial communications and I/O expansion, respectively. As you’ve probably gathered by now, SPLat/PC simulates the entire operation of the controller; you don’t even need to have the CC16 connected to test your program! However, if it is connected, the controller acts as a “dumb” I/O device. This means that input/output instructions executed in SPLat/PC act indirectly on the controller’s port lines (albeit slower than in real time), allowing in-situ testing and debugging. Using just 14 instructions that make up Fast-track (see Table 1), we’ve no doubt that just about anyone could write a rudimentary SPLat program in short order. And once you’ve got those down pat (or if you’re already a programming expert), you’ll be able to build up your repertoire from some 24  Silicon Chip 400 instructions that make up the complete instruction set! Multi-tasking Multitasking is a common requirement in industrial automation, so it makes sense to build support for this right into the programming language. SPLat’s integrated multi-tasking capabilities are called “MultiTrack” and are almost as easy to use as Fast-track! Remember our programming example from Fig.2? Imagine for a moment that this simple section of code controls a bottle capper on an assembly line. What changes might be required to drive a multi-headed capper, where each head operates asynchronously? Believe it or not, the necessary program is barely more complicated than the original, once we’ve added a few MultiTrack instructions – see Fig.6. Moreover, the program is easily expanded to handle many more channels or other “simultaneous” tasks. Don’t be fooled by the simplicity of our example. MultiTrack can be used to build sophisticated routines with inter-task communication and multiple 24-bit timers, with the latter limited only be available memory space. MultiTrack also provides a useful framework for libraries of common functions. According to SPLat, sample library style programs will be available in the future for a range of common functions. Expansion If your application demands more than 16 I/O lines, the CC16 is easily expanded via its SPI-like serial bus. SPLat offers a range of compatible 8-bit and 16-bit expansion boards, one of which features eight heavyduty 20A relays and eight optically isolated inputs. Additionally, the CC16 supports the industry standard Modbus protocol and can act as a Modbus RTU slave. Presumably, this would function over the TTL level “Comms” interface, as the low-cost CC16 doesn’t include an RS232 interface. Check it out As mentioned earlier, SPLat/PC siliconchip.com.au Table 1: Fast-Track Instruction Set WaitOn i Wait for input i to turn on WaitOff i Wait for input i to turn off WaitOnT i,tttt Wait for input i to turn on, timeout after tttt x 10ms WaitOff i,tttt Wait for input i to turn off, timeout after tttt x 10ms GoTo line Go to line GoIfT line Go to line if the expected input did occur in the preceding WaitOnT or WaitOffT instruction GoIfF line Go to line if the preceding WaitOnT or WaitOffT timed out Pause tttt Pause the program tttt x 10ms On o Turn on output o Off o Turn off output o SetMem m,cc Set memory location m to value cc DecMGoIfNZ m,line Decrement memory location m, go to line if the result is not equal to zero GoIfInOn i,line Go to line if input i is on GoIfInOff i,line Go to line if input i is off simulates the controller in software, so you can use simple code examples to learn more about the system even without a controller attached. Note that as the same software drives all of SPLat’s controllers, you must first specify the controller that you wish to simulate. This is done via the File -> Configure -> Board Type menu in the Editor; simply choose “CC16” from the drop-down list. The on-line mini-tutorials (accessible from the Help menu) are definitely worth a look too – they’ll have you writing your own code in less than a couple of hours! SPLat/PC can be Fig.5: the Input/Output window indicates the status of all of the CC16’s output lines using graphical “LEDs” and inputs using graphical “slide switches”. Any input can be simulated as high or low by altering the respective switch position with a mouse click. Inputs can also be momentarily set (simulating a pushbutton switch) by simultaneously holding down the Shift key. downloaded from www.splatco.com. au. Special offer Until 31st May 2007, SPlat Controls are offering a very special deal for SILICON CHIP readers interested in purchasing the CC16 development kit. To find out more, check out this “special offer” web address: www. splat-sc.com. SPLat Controls design, manufacture and support their products in Australia. They are situated in Seaford, Victoria and can be contacted on (03) SC 9773 5082. Fig.6: multitasking is built into the CC16 and it allows separate “slices” of a program (in this case TaskA and TaskB) to run simultaneously and independently of one another. Essentially, SPLat’s simple multitasking instructions allow less experienced users to write more sophisticated programs. The CC16BB Breakout Board is a useful add-on device to have during development, as it provides convenient screw terminal connections for power and all I/O connections, plus indicator LEDs on all I/O lines and DIP switches for activating inputs. It simply plugs into the four I/O connectors on the CC16 board. siliconchip.com.au April 2007  25