1 files changed, 66 insertions, 0 deletions
diff --git a/usi_spi.h b/usi_spi.h
new file mode 100644
index 0000000..18534ab
--- /dev/null
+++ b/usi_spi.h
@@ -0,0 +1,66 @@
+#include <avr/io.h>
+#include <avr/interrupt.h>
+#include <stdint.h>
+
+#include "mcu/mcu_def.h"
+
+#ifndef _IOE_USI_SPI_H_
+#define _IOE_USI_SPI_H_
+
+#ifndef MCUSUPPORT_USI
+#error "No USI interface is known on your mcu."
+#endif
+
+enum usiSpiMode {
+    // Device is initialized as master
+    USI_SPI_MODE_MASTER,
+    // Device is initialized as slave
+    USI_SPI_MODE_SLAVE,
+};
+
+/*
+ * Initialize SPI on USI device
+ *
+ *  Parameters:
+ *    mode - Specify mode of SPI interface
+ */
+void usi_spi_init(enum usiSpiMode mode);
+/*
+ * Returns NULL when device is not busy.
+ * When device is busy return values in non-zero.
+ */
+int8_t usi_spi_busy(void);
+/*
+ * Blocks processor until device is not busy.
+ */
+void usi_spi_join(void);
+/*
+ * Swap bytes with slave over SPI.
+ * This function blocks execution until device isn't busy.
+ * WARNING: Invoke this only when interface is initialized in MASTER mode.
+ */
+uint8_t usi_spi_send(uint8_t data);
+/*
+ * Swaps byte with slave over SPI.
+ * This function isn't checking if device is busy, but it's not blocking execution.
+ * WARNING: Invoke this only when interface is initialized in MASTER mode.
+ */
+uint8_t usi_spi_transfer(uint8_t data);
+/*
+ * Expose data for next master request.
+ * Please don't use this when device is busy.
+ * Best place to call this is usi_spi_retrieve().
+ * WARNING: Invoke this only when interface is initialized in SLAVE mode.
+ */
+void usi_spi_expose(uint8_t data);
+
+/*
+ * This function must be defined by user.
+ * This function is called every time transfer is finished.
+ * And until return from this function interrupts are disabled.
+ * WARNING: Please define this function in your code.
+ */
+void usi_spi_receive(uint8_t data);
+
+
+#endif /* _IOE_USI_SPI_H_ */