Greetings!
I am evaluating Host Firmware Upgrade process with a cellular notecard, output of card.version is below:
{
"version": "notecard-3.4.1.15128",
"device": "dev:864475040539180",
"name": "Blues Wireless Notecard",
"sku": "NOTE-NBGL-500",
"board": "1.11",
"api": 3,
"body": {
"org": "Blues Wireless",
"product": "Notecard",
"version": "notecard-3.4.1",
"ver_major": 3,
"ver_minor": 4,
"ver_patch": 1,
"ver_build": 15128,
"built": "Aug 11 2022 18:38:27"
}
}
Before investing more time and building a robust DFU setup on the host side, I have built a shell interface with some Notecard API commands, to get a better feeling how the DFU process works and what will be needed in my firmware.
I have logic analyzer attached to the UART lines. I can see the logical level as well has the analog level of the lines.
I am experiencing a weird behavior where Notecard randomly shuts down and I am not able to communicate with it. When this happens the TX line of the Notecard goes low.
You can see this on the bottom screenshot.
This happens in different cases:
- I am communicating with the Notecard (TX line goes down immediately, or after a few seconds)
- Or I am just waiting and not talking to the Notecard.
I am powering my entire board (and thus also Notecard) from a power supply set to 3.8V and 3A.
As you can see there are some voltage drops on the RX from MCU line (TX line from Notecard). They reach down to 3.3V. When this is happening the power supply shows around 400mA draw (I know shown current draw is averaged and the peaks are probably higher).
We were using thinner wires at some point, and voltage drops went down to 2.2V. We replace the wires with bulkier ones, and the current state is seen on the above screenshot.
I want to emphasize that shutdowns do not follow any repeatable pattern. I used the same setup for the whole day, and for the most of it I could download the firmware image, see the payload string and switch back to continuous mode. I did few shutdons, but since last two hours this now happens regularly, about a minute after I power reset the Notecard.
Only after the power reset of the Notecard, I can communicate again.
The only thing between the power supply and the power pins of the Notecard is a power load switch (SIP32431DR3-T1GE3) and two fuses (0ZCG0110BF2B, one for VIO_P, one for V_MODEM_P).
I hope that you can help with this somehow, if you need anymore information ask.