Some 2.8 Controller boards failing QA at higher than desired rates on QA step 18

[BrianAdams]

On step 18 is our burning the fuses on the mega2560. Debugging shows that the mega2560 is talking via the ISP communication, but that the attempt to put it in programming mode fails.

Good board

avrdude: Send: . [1b] . [0d] . [00] . [0c] . [0e] . [10] . [c8] d [64] . [19] [20] . [00] S [53] . [03] . [ac] S [53] . [00] . [00] > [3e]
avrdude: Recv: . [1b]
avrdude: Recv: . [0d]
avrdude: Recv: . [00]
avrdude: Recv: . [02]
avrdude: Recv: . [0e]
avrdude: Recv: . [10]
avrdude: Recv: . [00] -> OK
avrdude: Recv: . [0a]
avrdude: AVR device initialized and ready to accept instructions

Bad Board

avrdude: Send: . [1b] . [0d] . [00] . [0c] . [0e] . [10] . [c8] d [64] . [19] [20] . [00] S [53] . [03] . [ac] S [53] . [00] . [00] > [3e]
Read Sig
Ret Addr
OK
CMD1 CMD2
CMD_ENTER_PROGMODE_ISP

avrdude: Recv: . [1b] -> Command
avrdude: Recv: . [0d] -> Matched previous sequence number/register
avrdude: Recv: . [00] -> OK
avrdude: Recv: . [02] -> Respon Body length
avrdude: Recv: . [0e] -> Begininig of response body
avrdude: Recv: . [10] -> CMD_ENTER_PROGMODE_ISP
avrdude: Recv: . [c0] -> STATUS_CMD_FAILED
avrdude: Recv: . [ca] -> Checksum
avrdude: stk500v2_command(): command failed
avrdude: initialization failed, rc=-1
Double check connections and try again, or use -F to override
this check.

[WaltHolm]

The problem was isolated to a bad batch of ATMega2560s. They are being swapped out at the assembly house.