1 files changed, 71 insertions, 0 deletions
diff --git a/fw/dac.c b/fw/dac.c
new file mode 100644
index 0000000..0c9fb90
--- /dev/null
+++ b/fw/dac.c
@@ -0,0 +1,71 @@
+#include <xc.h>
+
+#include <stdint.h>
+
+#include "system.h"
+#include "types.h"
+#include "spi.h"
+
+#include "dac.h"
+
+// Configuration bits:
+// buffered, gain=1x, mode=active
+typedef enum {
+	CONFA = 0x70, // DAC A
+	CONFB = 0xF0, // DAC B
+} Conf;
+
+void
+dacInit(void) {
+	DAC1_CS_TRIS = OUT;
+	DAC2_CS_TRIS = OUT;
+	DAC1_CS = 1;
+	DAC2_CS = 1;
+
+	U16 level = {0u, 0u};
+	dacSet1a(level);
+	dacSet1b(level);
+	dacSet2a(level);
+	dacSet2b(level);
+}
+
+static void
+set(U8 dacNum, Conf conf, U16 level) {
+	lshiftU16(&level, 2u); // D0 at bit 2
+	level.hi = (U8)conf | (level.hi & 0x0F); // set config bits
+
+	if (dacNum == 1u) {
+		DAC1_CS = 0;
+	} else {
+		DAC2_CS = 0;
+	}
+	_delay(1);
+
+	(void)spiTx(level.hi);
+	(void)spiTx(level.lo);
+
+	if (dacNum == 1u) {
+		DAC1_CS = 1;
+	} else {
+		DAC2_CS = 1;
+	}
+}
+
+void
+dacSet1a(U16 level) {
+	set(1u, CONFA, level);
+}
+
+void
+dacSet1b(U16 level) {
+	set(1u, CONFB, level);
+}
+
+void
+dacSet2a(U16 level) {
+	set(2u, CONFA, level);
+}
+void
+dacSet2b(U16 level) {
+	set(2u, CONFB, level);
+}