Based on a PIC 18F458 from Microchip the presented board will run IPS (Interpreter for Process Structures) as it's operating system. IPS is in use as the operating system of some amateur radio satellites for example the AMSAT OSCAR-40 or AO-40 for short. More infos about IPS can be found at the AMSAT IPS page (DOS, Windows) or at IPS for Linux/UNIX. IPS is something like Forth which is also used in a lot of space applications shown on this page at NASA.
This Board is just a prototype design. It does not use SMD components (except 1 component) and is only a single sided PCB (with some links). So there should be no problem for building your own IPS board. No need for making double sided PCB's and soldering super small SMD parts. There will be another version of this board using only SMD parts and double sided PCB. This will shrink the board size by a factor of 2 to 3.
There will be also an expansion board which fits onto the IPS board.
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The IPS board consists of the MCU (a PIC 18F458), 2 x 32K SRAM, 64K EEPROM, 74HCT537 address latches, a MAX232 RS232 driver, I2C bus, 8 x I/O select, 5V power stabilisation, reset circuit and the connectors. There will be an expansion board with additional features like more EEPROM, Real Time Clock with battery backup, LCD, Buttons and DDS.
For the RS232 connecter I used a RJ45 connector because of space. The pins are numbered the same as on a conventional DB9 RS232 connector. So pin 1 on the DB9 is pin 1 on the RJ45 and so on. To connect the IPS board to a PC use a strait through cable from RJ45 to DB9 and Hyperterm on your PC. Set hyperterm to 9600 baud, 8 databits, no parity, 1 stop bit and hardware handshake. The last is important when uploading programs to the IPS board.
Image 1: The PCB
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Image 2: Component positions
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Image 3: Component positions
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You can download a PDF File with the schematic and the PCB here.
If you
dont have the Adobe Acrobat Reader installed on your machine you can find it here
Image 4: The etched PCB
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Image 5: The finished PCB with all components
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Image 6: The board including the AddOn board
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Image 7: Both boards stacked together
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Image 8: The board in action
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When the '*' is displayed you have 5 seconds to send a '-' to the board. In this case the board enters setup mode (much like a standard PC where you have to press ESC, DEL or F2 to enter the setup). This mode is called monitor mode. Here you have acces to neraly all low level functions of the IPS board like erasing and testing the main memory, installing new IPS firmware flashes, setting the time, defining the boot EEPROM and various other test and debug functions.
A detailed description of the monitor mode (aka Bios) will be published here when it is finished. Meanwhile the latest hex file for flashing a PIC 18F458 is available for download here. After flashing and powering up the board you should see the bios screen on a connected RS232 Terminal.
Welcome to IPS IPS Monitor V1.0 ? Show this help screen > Load Intel HEX File < Dump SRAM to Console # Test SRAM / Clear SRAM \ Show Byte at Address = Show Address Pointer _ Set Address Pointer and edit SRAM & Save SRAM --> EEPROM % Restore EEPROM --> SRAM ~ Show/Set real time clock - Configure Servos * Restart System |
The addon board will contain a LCD, battery charger circuit, I2C-Servo controller, temperature sensor, two buttons, two I2C eeproms to store IPS images (programs), an I2C extender and a battery backed real time clock. Again there are no SMT parts used and the PCB is single sided only with just a few wire bridges.
73, OE1RIB