I've pushed a major board layout change to bobc via github.
We've gone back to driving the FETs directly out of the ESTOP drivers using 5V, (using HCT/ACT chips) for the moment. Also increased the board size by 6mm to 95mm x 100mm. Moved the '125 closer to the 4 FETs it drives (need the space in the middle of the board and it reduces drive impedance to the FETs), and added an eeprom (same one as on RADDS, and on the same pins).
Regarding current, we've already mentioned we need more current so that would be my guess too, though admittedly with the Mega, drawing current from IOREF is probably a bad idea.
Note: We're nowhere near anything stable yet. There's a bunch of other changes to come and bugs to address before we're ready to consider making another run of boards.
We've gone back to driving the FETs directly out of the ESTOP drivers using 5V, (using HCT/ACT chips) for the moment. Also increased the board size by 6mm to 95mm x 100mm. Moved the '125 closer to the 4 FETs it drives (need the space in the middle of the board and it reduces drive impedance to the FETs), and added an eeprom (same one as on RADDS, and on the same pins).
Regarding current, we've already mentioned we need more current so that would be my guess too, though admittedly with the Mega, drawing current from IOREF is probably a bad idea.
Note: We're nowhere near anything stable yet. There's a bunch of other changes to come and bugs to address before we're ready to consider making another run of boards.