From a16510eb1fef4e8fdec4b2796a28f337d7f1e96d Mon Sep 17 00:00:00 2001
From: jim <jim@ddd99763-3ecb-0310-9145-efcb8ce7c51f>
Date: Fri, 29 Feb 2008 16:50:47 +0000
Subject: [PATCH] Sort of works.

git-svn-id: https://bucket.mit.edu/svn/nilm/zoom@6034 ddd99763-3ecb-0310-9145-efcb8ce7c51f
---
 firmware/zoom.c | 39 ++++++++++++++++++++++-----------------
 1 file changed, 22 insertions(+), 17 deletions(-)

diff --git a/firmware/zoom.c b/firmware/zoom.c
index f27c173..296da10 100644
--- a/firmware/zoom.c
+++ b/firmware/zoom.c
@@ -11,41 +11,44 @@ int send_data = 0;
 uint16_t send_adc, send_dac;
 
 /* Outside these thresholds, we step the DAC value */
-#define ADC_MIN 0x0100
-#define ADC_MAX 0x0e00
+#define ADC_MIN 0x074b
+#define ADC_MAX 0x08b3
 
 /* Max/min DAC output value */
 #define DAC_MIN 0x0000
-#define DAC_MAX 0x0fff
+#define DAC_MAX 0xffff
 
-/* Shift the DAC value left this far when writing it out */
-#define DAC_SHIFT 4
+/* A DAC step is this many counts */
+#define DAC_STEP 0x0080
 
 uint16_t dac_cmd = ((uint32_t)DAC_MAX + DAC_MIN) / 2;
 
 /* 128 KHz, after each ADC sample */
 void fast_callback(void)
 {
-	uint16_t v = adc_dmabuf[adc_offset];
-
-	if (v < ADC_MIN && dac_cmd < DAC_MAX)
-		dac_cmd ++;
-	else if (v > ADC_MAX && dac_cmd > DAC_MIN)
-		dac_cmd --;
-	else
-		return; /* No new command */
 
-	/* Write new value to DAC */
-	dac_write(dac_cmd << DAC_SHIFT);
 }
 
 /* 8 KHz, after DMA buffer filled */
 void slow_callback(void)
 {
+	/* Get most recent sample. */
+	uint16_t v = adc_dmabuf[adc_offset];
+
 	/* Send most recent sample to PC */
-	send_adc = adc_dmabuf[adc_offset];
+	send_adc = v;
 	send_dac = dac_cmd;
 	send_data = 1;
+
+	/* Update DAC if necessary */
+	/* TODO: Increase step depending on how far from ADC_MIN/ADC_MAX we are */
+	if (v < ADC_MIN && dac_cmd < (DAC_MAX - DAC_STEP)) {
+		dac_cmd += DAC_STEP;
+		dac_write(dac_cmd);
+	} else if (v > ADC_MAX && dac_cmd > (DAC_MIN + DAC_STEP)) {
+		dac_cmd -= DAC_STEP;
+		dac_write(dac_cmd);
+	}
 }
 
 void send_to_pc(void)
@@ -69,8 +72,9 @@ int main(void)
 	dac_init();
 	adc_init();
 //	adc_adc_callback = fast_callback;
-//	adc_dma_callback = slow_callback;
+	adc_dma_callback = slow_callback;
 
+/*
 	{ 
 		int16_t i = 0;
 		while(1) {
@@ -80,6 +84,7 @@ int main(void)
 			uart1_crlf();
 		}
 	}
+*/
 			
 	while(1) {
 		if (send_data) {