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SD card I2c Pin Expander

PostPosted: Sat Dec 12, 2015 6:36 pm
by rajdarge
I need to save data to my SD card with my espER

its a 12E but I still haven't worked out how to use pins 9,10 without causing a reset.

So I need SPI to write to the SD card.

I have a slave PRO mini that can translate and save the datalog but I wanted a history buffer to display on my LCD that is currently connected to the ESP8266-12e
I also wanted to put a rotary encoder on there so I can scroll through the history on the LCD.
I was planning to move all the LCD code to the pro mini, but only because I ran out of pins. The ESP seems to be handling the lot at the moment.


I have 2pins(RTC 20x4LCD) 3pins(TM1638qyf) and 1pin(5xds18b20's).

I have pin 16, 0, and 15 free. I wanted to keep pin 16 available for the "deep sleep" modes that I want to utilise to save power.

So can I use an 12c pin expander to create some extra pins to use for the spi?
or is that naf? and stupid and unwise?

Re: SD card I2c Pin Expander

PostPosted: Sat Dec 12, 2015 6:58 pm
by martinayotte
rajdarge wrote:So can I use an 12c pin expander to create some extra pins to use for the spi?
or is that naf? and stupid and unwise?


For SPI_CS, probably since it is lower speed, but not for SCK/MOSI/MISO, it would be slower than a turtle. ;)