[Ovmsdev] OVMS v3.3 hardware

Craig Leres leres at xse.com
Sun Dec 12 06:10:10 HKT 2021

I've made a tiny bit of progress with my sim7600a ppp issue.

First I realized that I could now run the master branch. The first test 
I did with my dev/7600 actually stayed connected to ppp for more than 14 
hours... I went looking for differences in my for-v3.3 and master builds 
and discovered my for-v3.3 tree was still using wolfssl. So I thought I 
had found the problem until 12 hours later when the dev unit lost ppp again.

I also see that it's possible to get ppp back up without rebooting by 
powering cell down (power cell off), waiting for that to complete, and 
then powering back up.

I went looking for additional things to log. I have cellular, 
cellular-modem-auto, and cellular-modem-factory set to verbose and 
gsm-mux and gsm-ppp set to debug. What else would be helpful?

I was reviewing this thread and found this:

On 9/6/21 23:28, Michael Balzer wrote:
 > I also added counters for these, you can query them with the "simcom
 > status debug" command:
 >> OVMS# sim stat deb
 >> Network Registration: RegisteredHome
 >> Provider: congstar
 >> Signal: -97 dBm
 >> State: NetMode
 >>   Ticker: 73099
 >>   User Data: 0
 >> ***  HW FIFO overflows: 21*
 >>   Buffer overflows: 0
 >>   Mux
 >>     Status: up
 >>     Open Channels: 4
 >> ***    Framing Errors: 24*
 >>     Last RX frame: 1 sec(s) ago
 >>     RX frames: 151452
 >>     TX frames: 5472
 >> PPP: Connected on channel: #2
 >> GPS: Connected on channel: #1
 >>      Status: enabled

Indeed I see one fifo overflow on my dev (which has lots ppp one time 
since boot):

     OVMS# cell status debug
     MODEM Status
       Model: SIM7600
       Network Registration: RegisteredRoaming
         Provider: AT&T Hologram
         Signal: -83 dBm
         Mode: LTE,Online
       State: NetMode
         Ticker: 1434
         User Data: 0
         FIFO overflows: 1
         Buffer overflows: 0
         Parity errors: 0
         Frame errors: 0
         Driver Buffer overflows: 0
       Mux: Status up
         Open Channels: 4
         Framing Errors: 0
         RX frames: 1864
         TX frames: 78
         Last RX frame: 0 sec(s) ago
       PPP: Connected on channel: #2
       GPS: Connected on channel: #1
          Status: enabled
          Time: enabled

I'm not sure if modem::modem() gets called when you power down/up the 
modem so I don't know if m_err_uart_fifo_ovf has been zero'd since boot.

On 9/6/21 18:35, Mark Webb-Johnson wrote:
 >> Is it too soon to add the v3.3 and v1.3 pdfs to the source tree?)
 > Yes, we haven’t finalised those, or gone through certification yet.
 > We’ll release the v3.3 main board and modem layouts and schematics when
 > that is complete (probably November/December timeframe).

I was thinking if I had the v3.3 modem schematic I could upgrade my 
boards to have uart hardware flow control. (I'm guessing if I had this I 
would not expect to see fifo overflows?)

Would it be useful for me to setup a way for you (Mark) to connect to my 
dev unit and interact with it while it is in the failed state?


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