For anybody who is interested I have a fix for the PB4 errata on Maple R5, R6 boards. It
requires two trace cuts, one on the top and one on the bottom of the board, and one jumper
on the bottom of the board.
NOTE: This should only be done by someone with at least some experience doing PCB
modifications. That said, it is an easy mod to make for someone with that
experience.
I have modified a two page PDF drawing to show where the cuts are made and where the
jumper is placed. Since there is no way to add attachments in this forum I sent the
PDF to Leaflabs via email and they should be able to make it available to forum members.
The bottom of the board is on page 1, and the top of the board is on page 2. The cuts
are marked by red Xs and the jumper is the red line with the via pads it is soldered
to marked with red circles (note that X on the bottom of the board is right next to the
circled via). Using the through-hole via pads for the jumper makes it much easier to
solder in place. The jumper is standard 30 ga. solid wire wrap wire. I used a very small
drill bit (#80) to remove the mask from the center of the vias so that the very short
length of stripped jumper wire could be inserted into the vias to help hold it in place.
I used a drill bit slightly larger than the via pads to VERY GENTLY remove the mask from
the pads for soldering. Or you could just VERY GENTLY scratch it off with knife used to
cut the traces.
After the mod is made the PB4 pin (56) is only connected to the JTAG connector pins (1, 8).
The processor NRST pin (7) is still connected to R4, the reset push button pins (2, 4) and
the J4 pin (1). All of these were verified using a digital multi-meter. After verifying the
mod, the board was powered up and functioned normally. I could not however verify the JTAG
interface because I do not have the hardware/software to do so.
