Hello,
First off, the reason you're not seeing any Serial Monitor data from the TinyZero when using the program you attached is because you need to use the SerialUSB object rather than Serial to be compatible with the SAMD21 processor.
The MicroSD TinyShield examples on the Learn page (
https://learn.tinycircuits.com/Memory/MicroSD_TinyShield_Tutorial/) make them usable for both the TinyZero and TinyDuino with the following code:
// Make program compatible for all TinyCircuits processor boards
#if defined(ARDUINO_ARCH_SAMD)
#define SerialMonitor SerialUSB
#else
#define SerialMonitor Serial
#endif
You can use the examples on that page which already work. If you want to adapt the code you attached, the SPI pins are listed on the Learn Page under Technical Details, as well as on the product page:
SPI Interface used:
10 - CS: This signal SPI chip select for the microSD card
11 - SCLK: This signal is the serial SPI clock out of the TinyDuino and into the microSD card.
12 - MISO: This signal is the serial SPI data out of the microSD card and into the TinyDuino.
13 - MOSI: This signal is the serial SPI data out of the TinyDuino and into the microSD card.
Hope that helps!
Best,
RĂ©na