From 631204a1feffa8cf3795060370b14dfb9f53f533 Mon Sep 17 00:00:00 2001
From: Camil Staps
Date: Tue, 31 Jan 2017 23:15:28 +0100
Subject: WIP

---
 spi.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)
 create mode 100644 spi.c

(limited to 'spi.c')

diff --git a/spi.c b/spi.c
new file mode 100644
index 0000000..f20f732
--- /dev/null
+++ b/spi.c
@@ -0,0 +1,61 @@
+#include <xc.h>
+#include "spi.h"
+
+void spi_init(void) {
+	SSPSTAT = 0x40;
+	SSPCON1 = 0x2a;
+	SSPADD = 39; // 200 kHz @ 32MHz
+
+	SPI_SDI = 0;
+	SPI_SCK = 0;
+	SPI_SDO = 0;
+
+	SPI_SDI_TRIS = 1;
+	SPI_SCK_TRIS = 0;
+	SPI_SDO_TRIS = 0;
+
+	SSPCLKPPS = SPI_SCK_PPS_IN;
+	SSPDATPPS = SPI_SDI_PPS;
+
+	SPI_SCK_PPS_OUT = 0x21;
+	SPI_SDO_PPS = 0x23;
+}
+
+uint8_t spi_exchange(uint8_t data) {
+	SSPCON1bits.WCOL = 0;
+	SSPBUF = data;
+	while (!SSPSTATbits.BF);
+	return SSPBUF;
+}
+
+uint8_t spi_exchange_buffer(uint8_t *in, uint8_t buflen, uint8_t *out) {
+	uint8_t written = 0;
+
+	if (buflen != 0) {
+		if (in != NULL) {
+			while (written < buflen) {
+				if (out == NULL)
+					spi_exchange(in[written]);
+				else
+					out[written] = spi_exchange(in[written]);
+				written++;
+			}
+		} else if (out != NULL)
+			while (written < buflen)
+				out[written++] = spi_exchange(DUMMY_DATA);
+	}
+
+	return written;
+}
+
+inline bool spi_is_buffer_full(void) {
+	return SSPSTATbits.BF;
+}
+
+inline bool spi_has_write_collision_occured(void) {
+	return SSPCON1bits.WCOL;
+}
+
+inline void spi_clear_write_collision_status(void) {
+	SSPCON1bits.WCOL = 0;
+}
-- 
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