ESP32 Forum

Hi,

Please see the attached schematic of ESP32-C3-MINI-1 circuit. Power on state keeps the EN pin at the "0" state for about 30 seconds until the MCU ends some functions then the EN pin goes to the "1" state. MCU Sending AT command, but no reply.
I have the endless loop of printouts as below. The ESP32-C3-MINI-1 is a new chip from the SMT line, I need to use the chip on AT mode. I don't need to download any firmware. On power mode, I need to open the Bluetooth, serial mode. I want to communicate with PC using Bluetooth connectivity via the UART of the MCU. Baud Rate -115200

Thank you,

invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff

rodrik5000 wrote: ↑

Tue Oct 17, 2023 10:58 pm

I don't need to download any firmware.

You actually do. The chips flash is empty at this moment, you need to upload the esp-at firmware before it listens to AT commands.

Thank you very much for your prompt reply. I have already assembled PCBA, I thought that those modules came with firmware like GSM modules.

As seen in the picture the module already soldered, about 25 prototypes. had on a production 1500 PCBA, I suspended the production now. How can I download firmware now?

I have Tx, Rx pins and VCC connected a seen in the schematic
I need your kind help
Thank you

No, sorry, if you buy a module there's no guarantee what, if any, is in the flash. If you want them pre-flashed, we can do that, though: note that there's a MOQ for that and I'm not sure if that's >1500. If you want to go that way now or in the future, you can contact sales@espressif.com.

If you want to fix the boards as is, you need Tx, Rx, Gnd and GPIO9. (Looks like you have GPIO9 on R38, which is great as it's at least somewhat accessible.) Pulling GPIO9 low while booting the chip puts it in download mode, you can then use something like esptool.py or some other esp flash download tool to upload the AT firmware to flash.

Hi, Thank you for the reply, I need 1k-2K pcs. minimum every month, At command firmware downloaded. Thank you

rodrik5000 wrote: ↑

Thu Dec 07, 2023 1:55 am

Hi, Thank you for the reply, I need 1k-2K pcs. minimum every month, At command firmware downloaded. Thank you

As I said, please contact sales@espressif.com for this.

Hello,

Thank you for your support. For the current manufactured PCBA, I tried to upload AT firmware to the modules. It's not programming at all. I am in big trouble with the big order contract. I need your kind advice to solve the programming issue.

Meanwhile, I found a programmer which I am assuming is your product, and going to order a few of them.

I modified the schematic, before manufacturing the PCB and manufacturing, please review the last design. If it's ok, I will send it to production.

Thank you