Ok, so this is the surface mount, but still 100% all parts available nothing hard to find VPW transceiver hardware. Just checked it, this works in both 1x and 4x modes and if you just use the VPW translation circuits (top part of the drawing) then you could adapt these to any Arduino or PIC or Motorola processor you wanted. As is, the drawing contains an ATmega32U4, configured as per the ArduinoMicro style board. I'm going to verify footprints and make sure the layout isn't too tight for the supercheap board houses to do properly, and I'll send the schematics and board gerbers to whomever updates the Github stuff.
Technically the interface could be completely done in through-hole components but it'd be about the size of a postcard, but since we're working at baseband and the symbol rate is relatively low, it should still work in a through-hole board.
If you don't care about the ATMega32U4 and associated stuff that has to be there for it to work, and you only want the J1850VPW stuff, then start at the OBD-II connector and work from there-you'll see where it translates out to just the J1850VPWRX and J8150VPWTX lines. Yes, the two voltage regulators are both LM7805's, the D2PAK versions, and to get the 7.6v to transmit on the VPW bus, we just put four diodes in series from the GND leg of the voltage regulator to ground-this lifts the regulator 2.6v over ground, and provdes a 7.6v rail to the transmit assembly.
Since I cut a lot of unneeded junk out of this board that handled CANbus as well, I need to re-do the PCB layout. I'll get it posted up as soon as possible.
Originally Posted by Xnke
Ok, so this is the surface mount, but still 100% all parts available nothing hard to find VPW transceiver hardware. Just checked it, this works in both 1x and 4x modes and if you just use the VPW translation circuits (top part of the drawing) then you could adapt these to any Arduino or PIC or Motorola processor you wanted. As is, the drawing contains an ATmega32U4, configured as per the ArduinoMicro style board. I'm going to verify footprints and make sure the layout isn't too tight for the supercheap board houses to do properly, and I'll send the schematics and board gerbers to whomever updates the Github stuff.
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