V2.1 boards, ESP-01 modules, and MaxiTerm

Author	Message
Seamus Newbie Joined: 18/08/2020 Location: United States Posts: 13	Posted: 12:13am 27 Oct 2024       Good day. It's been a good long while since I last posted anything here, but I recently got back on the CMM2, and have been enjoying it once again. With some interest from co-workers, I recently had a small batch of G2: V2.1 boards from the files linked in Peter's post of 10 July 2024. They arrived from the fab house, and all appears to be working as designed. In the interest of completeness, I am kitting these boards out with the batteries, jumper, SD card, and an ESP-01 module for wifi communications. ...and that's where I'm currently a bit stuck. I got a bunch of ESP-01 modules, flashed them with the Zimodem firmware (v3.4), and confirmed that this was working by visiting telnet BBSes on my desktop machine via the wifi modules. Plugging the modules into the CMM2 board, I get a red power LED to indicate the module is receiving power. Unfortunately, that's where it stops. I load up MaxiTerm on the CMM2, and I can get no response from the ESP-01 modules - not even a response from just an AT command. I have confirmed the communication parameters and speed settings, and am seeing no response from the module's activity LED to indicate that it is receiving any data from the CMM2. Looking at the schematics for the G2 board, it appears that the ESP01 header is connected to the COM2 port. I get no response from the module regardless of the port I tell MaxiTerm to use. Am I missing something? I have tried setting MaxiTerm to all different port numbers, and various speeds, but am seeing no response at all from the modules. At this point, I'm not sure what I'm doing wrong. Right now the ESP-01 functionality is the last hurdle for me to get over in order to have fully-functional units.
TassyJim Guru Joined: 07/08/2011 Location: Australia Posts: 6108	Posted: 01:35am 27 Oct 2024       The first thing I would do is remove the ESP-01 module and link the Tx and Rx pins. Then you can test the port by sending data and looking for the data echoed. That proves the correct port and the physical board traces are correct. You can use the ESP-01 from your PC so you know the correct baud rate etc. I can't think of anything else to test. Jim
Seamus Newbie Joined: 18/08/2020 Location: United States Posts: 13	Posted: 02:24am 27 Oct 2024       I just pulled the module and bridged the TX and RX pins as suggested. Everything loops through okay. I see the init string appear onscreen at MaxiTerm startup, and my keystrokes are echoed back as expected. So there's apparently an issue with the modules not talking, since I get none of that when they're installed. When I have the modules in the USB programmer they respond correctly and I am able to use them to connect to telnet BBSes, so I'm not sure just why they would work there but not in the CMM2 boards.
TassyJim Guru Joined: 07/08/2011 Location: Australia Posts: 6108	Posted: 03:41am 27 Oct 2024       If you have a cro, try monitoring the ESP Rx line and compare it with the working one on the USB programmer. You might need 2 stop bits or some other setting to match. Jim
Mixtel90 Guru Joined: 05/10/2019 Location: United Kingdom Posts: 6832	Posted: 06:34am 27 Oct 2024       If you are sending strings then try not sending CRLF. The ESP needs it, but it may be being set automatically unless your terminal is in binary mode.
javavi Senior Member Joined: 01/10/2023 Location: Ukraine Posts: 244	Posted: 07:55am 27 Oct 2024       Good day to all! I would also like to try this WiFi modem on ESP, but the only hardware I have for MMBASIC is PicoMite. Is there something similar to MaxiTerm for SMM2 only for PicoMite VGA?
matherp Guru Joined: 11/12/2012 Location: United Kingdom Posts: 9171	Posted: 08:01am 27 Oct 2024       Looks like the default baudrate for Zimodem is 1200. This is at the margin of what a CMM2 can handle. I suggest you connect a usb/uart to the esp and set it to 9600 or greater. Then try it with the CMM2. I can confirm the ESP slot is on COM2.
lizby Guru Joined: 17/05/2016 Location: United States Posts: 3156	Posted: 12:31pm 27 Oct 2024         javavi said   I would also like to try this WiFi modem on ESP, but the only hardware I have for MMBASIC is PicoMite. You should be able to have the PicoMite console be on Rx/Tx pins instead of through the USB connection, and then access the MMBasic command prompt as if you were using TeraTerm from the PC through USB.
homa Guru Joined: 05/11/2021 Location: Germany Posts: 351	Posted: 02:12pm 27 Oct 2024       @Seamus: I also had problems with that. It worked in the end. Here is my solution at the time. https://www.thebackshed.com/forum/ViewTopic.php?TID=16882&PID=220494#220494#221116 Matthias
Seamus Newbie Joined: 18/08/2020 Location: United States Posts: 13	Posted: 11:36pm 30 Oct 2024       UPDATE: Thank you for the replies about this topic. It has now been resolved. The problem, as it turns out, was my modules. Putting a scope on the TX and RX lines, it was quite apparent that the RX line level was not swinging low with any real authority. Trying again with another set of ESP-01s modules yielded better results, and all five boards are now functioning properly.
phil99 Guru Joined: 11/02/2018 Location: Australia Posts: 2149	Posted: 12:17am 31 Oct 2024       Perhaps those modules could be made usable with a pulldown resistor on the offending pin.
Seamus Newbie Joined: 18/08/2020 Location: United States Posts: 13	Posted: 12:43am 31 Oct 2024       I had thought of that as well. I will have to mess with them later, and they can certainly can be used in other projects either way.