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AT commands over I2C rather than UART?
Posted:
Sun Aug 09, 2015 3:17 am
by Jabz
Hi,
I just bought a ESP9266-01 module, very impressed by it. Though I need more bandwidth than UART can provide, is there firmware available that replaces UART with I2C, or possibly SPI?
Thanks in advance.
Re: AT commands over I2C rather than UART?
Posted:
Sun Aug 09, 2015 11:55 pm
by kolban
Howdy,
If one was using I2C or SPI then we wouldn't be sending AT commands ... but would instead have to invent our own protocol. While in principle we could send ASCII strings over these protocols, it would be an "odd" thing (opinion). However, if you can cite examples where I2C or SPI have been used to send strings, I'd be very interested.
Assuming you did wish to use I2C or SPI AND invented a command protocol ... then in principle, we have all the bits we need. The AT commands don't appear to do anything other than drive the publicly available SDK APIs.
My biggest thing though is questioning the value. Can you describe the nature of the data that you want to push through to the ESP? What kind of bandwidth are you trying to push? Which directions will the data be flowing?
Re: AT commands over I2C rather than UART?
Posted:
Mon Aug 10, 2015 4:02 am
by Jabz
Thanks for the reply.
The idea was to push a video stream from the OV7670 640*480p camera. Which would SPI to my mbed LPC1768 board, and hopefully I could repurpose the tx/rx lines to the ESP8266 to use I2C, which would provide enough bandwidth (400Kb - 3.1Mb) to send perhaps greyscale video.
Unfortunately my ESP8266 has since bricked. I was playing around with node-mcu, and I loaded a init.lua that changed the baud rate. This forced me to re-flash the module and now the blue LED is stuck on.
Re: AT commands over I2C rather than UART?
Posted:
Mon Aug 10, 2015 8:56 am
by martinayotte
From few reading, maybe I'm wrong, but the I2C bus on OV7670 is only used for control settings, the video stream itself is coming thru a 8 bits parallel port along with VSYNC/HSYNC signal. If video stream is also available thru I2C, I presume you won't get any good frame rate.