BoSL Board Debug

Stop logging issue

The BoSL Board stops logging from time to time is a big pain. The team decided to find the root cause and solve the problem.

Trouble shooting history

31th May 2023

20 BoSL boards were setup for trouble shooting. 10 run the original BoSL_logging.ino code, each one with a tag (OLD_1, OLD_2, ...), let's call them OLD group. Another 10 run Dave's new version code BoSL_VEL_Dave_290523.ino, each one with a tag (NEW_1, NEW_2, ...), let's call them NEW group. The major difference between OLD and NEW group is the NEW group's code delays longer to pull Sim7000 powerkey down to power off Sim7000. Because we suspect that some MCUs run slowly and the delay(1200) is less than accurate 1200ms, so sometimes Sim7000 may not really power off and the result is the Sim7000 runs out of order.

8th June 2023

Observed the 2 groups for one week. The result is both groups had some ones stop logging, 2 in NEW group and 2 in OLD group. The conclusion is: delay(1200) is not the cause of stop logging.
A logbook for the trouble shooting was created on the google drive, find it here.

15th June 2023

Lucky to catch 2 boards stop logging, NEW_1 and OLD_2. Luke and Felix did the test together. VPP Voltage, Sim7000 STATUS pin voltage, Sim7000 POWERKEY voltage were tested. We also used a Arduino UNO pass though board tested BoSL board TX output, Sim7000 TX and RX output.
NEW_1 was a Sim7000 issue as ATMega pulls down and up POWERKEY as expected and gives good ATCommands to Sim7000, but Sim7000 STATUS pin voltage always near 0V(5.7-5.8mV) and gives no reply to ATCommands.
OLD_2 turned out to be ATMega issue. The POWERKEY voltage was always near 0V in the test and we read nothing from Sim7000 RX pin, means no ATCommands were sent to Sim7000 by ATMega.
During the test with OLD_2, we noticed another problem with the board, OLD_2's VPP voltage dropped to 1.8V.