1 files changed, 54 insertions, 0 deletions
diff --git a/src/usi_spi.c b/src/usi_spi.c
new file mode 100644
index 0000000..01c37f7
--- /dev/null
+++ b/src/usi_spi.c
@@ -0,0 +1,54 @@
+#include "../usi_spi.h"
+#include "../mcu/mcu_def.h"
+
+inline void usi_spi_init(enum spiMode mode) {
+    if (mode == USI_SPI_MODE_MASTER) {
+        // Set USCK and DO as output
+        DDR_USI |= _BV(DD_USCK) | _BV(DD_DO);
+        // Set DI pull up resistor
+        PORT_USI |= _BV(PORT_DI);
+
+        USICR |= _BV(USIWM0) | _BV(USICS1) | _BV(USICLK);
+    } else {
+        // Set DO as output
+        DDR_USI |= _BV(DD_DO);
+        // Set USCK and DI pull up resistor
+        PORT_USI |= _BV(PORT_USCK) | _BV(PORT_DI);
+
+        USICR |= _BV(USIWM0) | _BV(USICS1) | _BV(USIOIE);
+    }
+}
+
+inline int8_t usi_spi_busy(void) {
+    if (interface == SPI_INTERFACE_USI)
+        return USISR & 0x0F;
+}
+
+inline void usi_spi_join(void) {
+    while (spi_busy(interface));
+}
+
+inline uint8_t usi_spi_send(uint8_t data) {
+    while (spi_busy(interface));
+    return spi_transfer(interface, data);
+}
+
+inline uint8_t usi_spi_transfer(uint8_t data) {
+    // TODO rewrite and this for noninterupt
+    if (interface == SPI_INTERFACE_USI) {
+        _spi_usi_busy = 1;
+        USISR |= _BV(USIOIF);
+        USIDR = d;
+        do {
+            USICR |= _BV(USITC);
+        } while (!(USISR & _BV(USIOIF)));
+        return USIDR;
+    }
+}
+
+inline void usi_spi_expose(uint8_t data) {
+    if (interface == SPI_INTERFACE_USI)
+        USIDR = data;
+}
+
+////// Interrupts ////////////////////////////////