Can't communicate with GEM via serial

[lwe]

I've been trying to communicate with my new GEM, but am not having any luck.

I chose to go with serial only, so I do not have Ethernet, Wifi, etc. modules. I've got power provided to the board via the 5VDC 1A adapter, and a CP2102 cable connected to COM1 RX, TX, and GND set at 115200 baud 8N1. Note that this was my own cable I had laying around -- I didn't receive one with the kit (not sure if I was supposed to or not?)

If I open up a serial terminal, I see the same (garbage?) data repeating again and again, but I cannot use "Get GEM info" button -- it just gives me an error with "Refresh error 2 0, Response data = , Data Length = 0". Trying with 19200 baud gives me a timeout error.

Opening the browser with 115200 baud spews garbage characters in the page.

I came across this thread which seems similar -- viewtopic.php?t=1283
Following the advice in that post, I tried flashing new COM firmware in recovery mode at 115200 and 19200 baud, get 222 timeout errors on both. I now seem to be stuck in firmware recovery mode.

Any tips on where to go from here?

[ben]

I've been trying to communicate with my new GEM, but am not having any luck.

I chose to go with serial only, so I do not have Ethernet, Wifi, etc. modules. I've got power provided to the board via the 5VDC 1A adapter, and a CP2102 cable connected to COM1 RX, TX, and GND set at 115200 baud 8N1. Note that this was my own cable I had laying around -- I didn't receive one with the kit (not sure if I was supposed to or not?)

If I open up a serial terminal, I see the same (garbage?) data repeating again and again, but I cannot use "Get GEM info" button -- it just gives me an error with "Refresh error 2 0, Response data = , Data Length = 0". Trying with 19200 baud gives me a timeout error.

Opening the browser with 115200 baud spews garbage characters in the page.

I came across this thread which seems similar -- viewtopic.php?t=1283
Following the advice in that post, I tried flashing new COM firmware in recovery mode at 115200 and 19200 baud, get 222 timeout errors on both. I now seem to be stuck in firmware recovery mode.

Any tips on where to go from here?

The kit doesn't come with the Serial-to-USB cable, just the unit itself.

If the garbage data repeats at a regular interval and fire when the GEM COM LED turns red, it's a packet leaving the GEM.

What's the GEMs Sys LED doing?

- Regular operation will be solid green with the occasional red flash.
- Stuck in F/W mode would be solid red.

Are you running this on a Windows PC?

[lwe]

The kit doesn't come with the Serial-to-USB cable, just the unit itself.

If the garbage data repeats at a regular interval and fire when the GEM COM LED turns red, it's a packet leaving the GEM.

What's the GEMs Sys LED doing?

- Regular operation will be solid green with the occasional red flash.
- Stuck in F/W mode would be solid red.

Are you running this on a Windows PC?

After leaving it unplugged for a while, it seems I'm no longer stuck in F/W recovery mode -- LEDs are flashing the way they did when I first powered on the GEM:

Top-left LED (labeled LED1) is consistently blinking red with an occasional green flash. Top-right LED (labeled LED2) is solid green.

I'm primarily using GEM Network Utility v8.0 on Windows. I've also tried poking at the serial interface via minicom on Linux.

[lwe]

Looking more closely, LED1 is blinking in a constant pattern: RED -> OFF -> RED -> OFF -> RED -> OFF -> RED -> GREEN -> RED -> OFF ...

[lwe]

Plugging in the 3.5 mm PT input has now changed LED1 to be solid green with an occasional red flash that lines up with the garbage data.

[lwe]

To verify, I tried a different CP2102 breakout board and a different USB cable, and ended up with the same results.

This + the fact that I'm receiving data (even though it looks like garbage) seems to imply that the issue isn't with the RS232 to USB converter, the USB cable, or the wiring to the COM1 terminals.

[lwe]

Hmm... now that I think about it, are COM1 and COM2 *actual* RS232 interfaces? I saw that the official Brultech cable used the "CP2102 chipset" and had a couple CP2102 breakout boards handy, and assumed that was all I needed. But maybe I need to convert from RS232 -> TTL first, with something like a MAX3232 chip, then connect that to the CP2102.

Or... maybe just buy the cable from the Brultech store

[lwe]

The kit doesn't come with the Serial-to-USB cable, just the unit itself.

I went back and double-checked the GreenEye Monitor Package product page: https://www.brultech.com/store/index.ph ... er=product

The description says "No module option comes with a DB9 cable for RS232 access", hence my confusion on there not being a cable included in the box.

[ben]

Hmm... now that I think about it, are COM1 and COM2 *actual* RS232 interfaces? I saw that the official Brultech cable used the "CP2102 chipset" and had a couple CP2102 breakout boards handy, and assumed that was all I needed. But maybe I need to convert from RS232 -> TTL first, with something like a MAX3232 chip, then connect that to the CP2102.

Or... maybe just buy the cable from the Brultech store

Ahh yeah, the GEM is RS232.

You can also use Amazon (especially if you have Prime) given shipping speed. Don't get a Prolific cable, that chipset has a lot fakes and drivers are built to mess with fake chips.

FTDI is a good one, that's what we source.

https://www.amazon.com/Sabrent-Serial-A ... 006AA04K0/

Contact sales(at)brultech.com about the missing DB9 cable. Tammy can help you out. We're off until the 29th however.

[lwe]

I was able to quickly get my hands on an RS232 to TTL level shifter breakout board, and now that I've got that sitting between the CP2102 and COM1, everything is working as it should. GEM Network Utility is happy and I can access the GEM's setup page via the browser. Success!

No worries on the cable -- I should be fine without one from here on out. Just thought I would bring it up since the product page was a bit confusing.

Thanks for your help, and enjoy the break!