ESP8266 Community Forum

As esp8266 works with SPI Winbond W25Q40BVNIG memory it wil be nice to get controll over SPI in general.
Both - software configured "virtual" and build-in hardware.

It will be good approach to work with SD-card.
Bootloader suports to treat MTDO (GPIO15) pin as selector to boot from (and work with) SD-card.
Then GPIO0 and GPIO2 work as SDIO interface.

Below is an image showing expanded GPIO12,13,14,15 pins - for software SPI...

SPI support for connecting sd cards will be really good, especially for data logging.

ucy74 wrote:As esp8266 works with SPI Winbond W25Q40BVNIG memory it wil be nice to get controll over SPI in general.
Both - software configured "virtual" and build-in hardware.

It will be good approach to work with SD-card.
Bootloader suports to treat MTDO (GPIO15) pin as selector to boot from (and work with) SD-card.
Then GPIO0 and GPIO2 work as SDIO interface.

Below is an image showing expanded GPIO12,13,14,15 pins - for software SPI...

use the spi master same as the one communicate with W25Q40, is almost impossible I think.
because, the code in the W25Q40 runs in XIP mode.
if the SDK get the spi slave/master driver work, it's easy to wrap in lua.

for the data log, maybe use the power of wifi/network/cloud?

for the data log, maybe use the power of wifi/network/cloud?

yes, but:
1. We can log data when network/cloud does not work. And transmit stored data to the cloud when network/cloud became reachable.
2. We can make "power-save" mode, when for example data from sensors is recorded every 1 minute and is transmitted to the cloud only every 10 minutes.
Networks and clouds can't be 100% reliable and work all the time. Sh*t can happen (= So it's good to be able to store data in some cases.