X-Git-Url: https://git.karo-electronics.de/?p=oswald.git;a=blobdiff_plain;f=metawatch%2Fmw_acc.c;fp=metawatch%2Fmw_acc.c;h=270f2467304894237492941ebf905ce38960adc7;hp=0000000000000000000000000000000000000000;hb=6029630643335ebe7dbba2da8e7bf2b5f7a434f9;hpb=b254c4abccb1ef8a6de4bd543b8135af071d5f7f

diff --git a/metawatch/mw_acc.c b/metawatch/mw_acc.c
new file mode 100644
index 0000000..270f246
--- /dev/null
+++ b/metawatch/mw_acc.c
@@ -0,0 +1,71 @@
+#include <msp430.h>
+#include <msp430xgeneric.h>
+#include <stdint.h>
+
+#include "mw_main.h"
+
+#include "mw_acc.h"
+
+void mw_init_acc_i2c(void)
+{
+	/* enable reset before configuration */
+	ACCELEROMETER_CTL1 |= UCSWRST;
+
+	/* configure as master using smclk / 40 = 399.5 kHz */
+	ACCELEROMETER_CTL0 = UCMST + UCMODE_3 + UCSYNC;
+	ACCELEROMETER_CTL1 = UCSSEL__SMCLK + UCSWRST;
+	ACCELEROMETER_BR0 = 42;
+
+	ACCELEROMETER_BR1 = 0;
+	ACCELEROMETER_I2CSA = KIONIX_DEVICE_ADDRESS;
+
+	/* release reset */
+	ACCELEROMETER_CTL1 &= ~UCSWRST;
+}
+
+/*
+ * DMA2 = SPI for LCD
+ */
+static void mw_acc_i2c_write_byte(uint8_t byte)
+{
+	ACCELEROMETER_TXBUF = byte;
+	while ((ACCELEROMETER_CTL1 & ACCELEROMETER_IFG) == 0)
+		nop();
+}
+
+/* OK this is polling write, but data is small and 400kHz I2C, it should "just work" :) */
+void mw_acc_i2c_write(const uint8_t addr, const void *data, const uint8_t len)
+{
+	int i;
+
+	if (len == 0) {
+		return;  
+	}
+  
+	while (UCB1STAT & UCBBUSY)
+		nop();
+  
+	/* 
+	 * setup for write and send the start condition
+	 */
+	ACCELEROMETER_IFG = 0;
+	ACCELEROMETER_CTL1 |= UCTR + UCTXSTT;
+	while (!(ACCELEROMETER_IFG & UCTXIFG))
+		nop();
+  
+	/* 
+	 * clear transmit interrupt flag,
+	 * send the register address
+	 */
+	ACCELEROMETER_IFG = 0;
+
+	mw_acc_i2c_write_byte(addr);
+
+	for (i=0; i<len; i++)
+		mw_acc_i2c_write_byte(*(uint8_t *)(data+i));
+
+	while (ACCELEROMETER_CTL1 & UCTXSTP)
+		nop();
+}
+
+