I need some advice.
I have designed a PCB using a ESP-WROOM-32 & SDMMC & CH340G.
The problem is that the CH340G uses the two transistors for set the programming mode.
If I have an SD card inserted into it's socket, the WROOM will not go into programming mode.
I release the SD card, and its fine.
Is there a correct schematic where the SD card does not interfere with the Boot process.
I know its the IO2 pin.
What is the proper circuit ?
The schematic attached is my pcb schematic.
ESP-WROOM-32 & SDMMC & CH340G
Re: ESP-WROOM-32 & SDMMC & CH340G
Please have a look at the wrover-kit schematic (https://docs.espressif.com/projects/esp ... s.html#id8). It has the additional transistor on GPIO2 to pull it low when entering download mode.
-
- Posts: 31
- Joined: Tue Mar 21, 2017 3:40 am
Re: ESP-WROOM-32 & SDMMC & CH340G
I added the extra isolation transistor, but I have the same proble.
I can not go into programming mode with the SD card inserted.
Please see attached schematic.
I can not go into programming mode with the SD card inserted.
Please see attached schematic.
- Attachments
-
- SDMMC_070319.pdf
- (28.73 KiB) Downloaded 591 times
Re: ESP-WROOM-32 & SDMMC & CH340G
Did you check oscilloscope? Maybe EN pin goes high before IO2 goes low because of no cap on EN + strong pull-up, and capacitive effects of SD card on IO2?
Who is online
Users browsing this forum: No registered users and 125 guests