1 files changed, 8 insertions, 0 deletions
diff --git a/src/samd21/gpio.h b/src/samd21/gpio.h
index f423f8ff..41787b85 100644
--- a/src/samd21/gpio.h
+++ b/src/samd21/gpio.h
@@ -21,6 +21,14 @@ struct gpio_in gpio_in_setup(uint8_t pin, int8_t pull_up);
 void gpio_in_reset(struct gpio_in g, int8_t pull_up);
 uint8_t gpio_in_read(struct gpio_in g);
 
+struct spi_config {
+    uint32_t ctrla, baud;
+};
+struct spi_config spi_setup(uint32_t bus, uint8_t mode, uint32_t rate);
+void spi_prepare(struct spi_config config);
+void spi_transfer(struct spi_config config, uint8_t receive_data
+                  , uint8_t len, uint8_t *data);
+
 struct i2c_config {
     uint8_t addr;
 };