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#32 — Redesign the mainboard

State Resolved
Release: 0.3
Area Core Hardware
Issue type Feature
Severity Important
Submitted by Sébastien Lelong
Submitted on 2008-01-05
Responsible Sébastien Lelong
Target release: 0.3
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Last modified on 2008-10-13 by Sébastien Lelong
I've recently begun to use PCB board, producing better results. Using Eagle, documentation is better and faster to produce. And boards can be far smaller... It's time to reconsider the mainboard (schematics/boards from Eagle, PCB board). It's also time to improve this board:

 * split 2x13 pins connector into:
   - 1 PORTA connector (2x5 pins). Since PORTA has 8 pins, the two remaining pins could be used to carry +5V (simplify connections).
   - 1 PORTB connector (2x5 pins), which will carry the communincation (RS232, I2C, SPI...). Also carry +5V.
   - several power connector for +5V (output from 7805)
   - several power connector for +12V or +9V (output from power supply).
 * LEDs showing RS232 output and input between PIC and PC
 * LEDs showing RS232 output and input between PIC and other daughterboards
 * push button for reset
 * resistor between MCLR and +5V (1k ?). Allow reset through RTS ?
 * wiring to allow reset from RS232
 * miniboard including XTAL and its caps (caps may change according to XTAL frequency). This also allows to completely remove the XTAL and uses the internal oscillator.
 * 2 resistors for I2C pins (SCL, SDA), connected to ground (1.8K or 2.2K should be ok).

Should the board also handles both 16F628 and 16F88, using a trigger ? No decided yet...
Added by Sébastien Lelong on 2008-01-05 11:46
Issue state: unconfirmedopen
Added by Sébastien Lelong on 2008-01-07 08:01
Issue state: openin-progress
Started design with Eagle. Board is quite big, actually bigger than before...

 - no Reset through RTS, don't know if I even use this feature
 - no LEDs for RS232 com. They keep lighting on, even if no data is written or read (because logical levels are inverted), and even if data is written or read (because too fast).
Added by Sébastien Lelong on 2008-01-24 08:14
Quite done... Board only supports 16F88. Problem with wiring + polarity (not normalized), see and
Added by Sébastien Lelong on 2008-10-13 07:49
Issue state: in-progressresolved
Done (it long time actually...)

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