- Fri Nov 14, 2014 10:24 am
#2613
It will be unpleasant to use the I2c LCD except via an external MCU ( ex. arduino )
First the esp8266 firmware is often very unstable..the manufacturer of the esp8266 has IMHO the most stable firmware. If you wish to have the esp8266 control your LCD via firmware it will not be an easy task given that the source code that's available for modification is very much a work in progress. The most reliable manufacturer's firmware uses a 3.3v rs232 interface. The baud rate is changeable but rs232 is also dependent on the Xtal freq luckily there is approx 1% tolerance in the baud rate but RS232 is often the less ideal choice. Next rs232 is asynchronous and this is less than ideal since it will require an interrupt driven ring buffer on any external MCU that is attached. If you use an external MCU you can make sense of the AT commands but it is very inelegant and requires an extensive parsing routine in the external MCU. The MCU would need to to send and receive the rs232 AT command and response stream. The MCU would then via I2c control your LCD. LCD's especially graphic LCD's can have a complex interface particularly when initiating.
The esp8266 has price on its side and removes the need to handle the TCP stack..Competitors like TI and Microchip make TCP stacks available for their WifI chips so its not too arduous.
When and open source code that compiles to robust firmware is perfected the esp8266 will be a good product
(the xtensa MCU would handle the external interface via it own GPIO pins and no external MCU would be needed).
With the current rs232 AT command interface it makes interfacing with an external MCU possible but mostly unpleasant.
IMHO if the AT commands and the RS232 interface were removed from the firmware and replaced with a more appropriate for an external MCU interface I2C SPI etc with 16 bit commands and 16 bit responses things could be pleasant.
