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SPI jumpers on SD Card shield v4.3

Posted: Wed Feb 20, 2019 8:42 pm
by paul_tanner
I want to use this card in an application that also features and SPI slave. So I need to check all the SPI pin assignments.
The shield has some jumpers which appear to be for this purpose. Even with a magnifying glass I can see exactly what these do.
Is there any documentation to allow me to use SD Card with software SPI on pins that are not used by hardware SPI? Eg. on Leonardo we would need to avoid using SCK 15; MOSI 16; MISO 14;

Re: SPI jumpers on SD Card shield v4.3

Posted: Thu Feb 21, 2019 12:05 pm
by bestlux
Hello, You mean you are using the Arduino board with the SDCard shield themselves as a slave of SPI that controlled by another host, so you need a soft SPI to feature as slave. I think this example can match your need: https://github.com/niteris/ArduinoSoftSpi

Re: SPI jumpers on SD Card shield v4.3

Posted: Thu Feb 21, 2019 8:57 pm
by paul_tanner
Thx @bestlux

After further work with a magnifying glass I determined that I needed to unlink row A of the jumpers (hard to cut tracks). And link row B. So now we have SD on 4; MOSI 11; MISO 12; SCK 13. I thought it should be possible to use the standard Arduino SD library with #define SOFTWARE_SPI to create an SPI master on those pins. That did not work.

Then I tried SD.begin with 4 params, specifying all SPI pins. This is working OK. Next step is to ensure this can co-exist with an SPI slave on the same Leonardo.