From b9defeee0288beba157a9a8143b4a28a95696e1a Mon Sep 17 00:00:00 2001
From: Mariano Alvira <mar@devl.org>
Date: Sun, 21 Oct 2012 11:38:37 -0400
Subject: [PATCH] small tweaks to how ADC channels are enabled.

---
 lib/adc.c         | 39 ++++++++++++++++++++++++---------------
 lib/include/adc.h |  9 +++++++++
 tests/adc.c       |  7 ++++++-
 3 files changed, 39 insertions(+), 16 deletions(-)

diff --git a/lib/adc.c b/lib/adc.c
index 841855107..efde94019 100644
--- a/lib/adc.c
+++ b/lib/adc.c
@@ -34,9 +34,7 @@
  */
 
 #include <stdint.h>
-#include "crm.h"
-#include "adc.h"
-#include "gpio-util.h"
+#include "mc1322x.h"
 
 //#define ADC_CHANS_ENABLED 0x3F // channels 0-5 enabled
 //#define ADC_CHANS_ENABLED 0x7E // channels 1-6 enabled
@@ -73,9 +71,26 @@ void adc_service(void) {
 	}
 }
 
-void adc_init(void) {
-	uint8_t n;
+#define _adc_setup_chan(x) do { \
+	if ( channel == x ) { \
+            ADC->SEQ_1bits.CH##x = 1; \
+            GPIO->FUNC_SEL.ADC##x = 1; \
+	    GPIO->PAD_DIR.ADC##x = 0; \
+            GPIO->PAD_PU_EN.ADC##x = 0; \
+}} while (0)
 
+void adc_setup_chan(uint8_t channel) {
+	_adc_setup_chan(0);
+	_adc_setup_chan(1);
+	_adc_setup_chan(2);
+	_adc_setup_chan(3);
+	_adc_setup_chan(4);
+	_adc_setup_chan(5);
+	_adc_setup_chan(6);
+	_adc_setup_chan(7);
+}
+
+void adc_init(void) {
 	ADC->CLOCK_DIVIDER = 80;       // 300 KHz
 	ADC->PRESCALE      = ADC_PRESCALE_VALUE - 1;       // divide by 24 for 1MHz.
 
@@ -114,13 +129,13 @@ void adc_init(void) {
 	ADC->SR_1_LOW        = (REF_OSC / ADC_PRESCALE_VALUE) / (115200 / 8) + 1;
 #endif
 
-	ADC->SEQ_1         = 0
+	ADC->SEQ_1         = 0;
 #if ADC_USE_TIMER
-		| (1 << 15) // sequence based on Timer 1.
+		ADC->SEQ_1bits.SEQ_MODE = 1; // sequence based on Timer 1
 #else
-		| (0 << 15) // sequence based on convert time.
+		ADC->SEQ_1bits.SEQ_MODE = 0; // sequence based on convert time.
 #endif
-		| ADC_CHANS_ENABLED;
+	ADC->SEQ_1bits.BATT = 1;
 
 	ADC->CONTROL       = 0xF001
 //#if ADC_USE_TIMER
@@ -129,10 +144,4 @@ void adc_init(void) {
 	;
 	ADC->OVERRIDE     = (1 << 8);
 
-	for (n=0; n<=8; n++) {
-		if ((ADC_CHANS_ENABLED >> n) & 1) {
-			gpio_select_function(30 + n, 1); // Function 1 = ADC
-			gpio_set_pad_dir(30 + n, PAD_DIR_INPUT);
-		}
-	}
 }
diff --git a/lib/include/adc.h b/lib/include/adc.h
index 66dfa1f8a..3d018e009 100644
--- a/lib/include/adc.h
+++ b/lib/include/adc.h
@@ -39,6 +39,9 @@
 #include <stdint.h>
 #include "utils.h"
 
+/* the Vbatt measurment reads about 200mV low --- trim by ADC_VBATT_TRIM */
+#define ADC_VBATT_TRIM 200
+
 /* ADC registers are all 16-bit wide with 16-bit access only */
 #define ADC_BASE        (0x8000D000)
 
@@ -153,8 +156,14 @@ static volatile struct ADC_struct * const ADC = (void *) (ADC_BASE);
 #define adc_enable()  (ADC->CONTROLbits.ON = 1)
 #define adc_disable() (ADC->CONTROLbits.ON = 0)
 #define adc_select_channels(chans) (ADC->SEQ_1 = (ADC->SEQ_1 & 0xFE00) | chans)
+void adc_setup_chan(uint8_t channel);
 
 extern uint16_t adc_reading[NUM_ADC_CHAN];
+/* use the internal reference to return adc_readings in mV */
+#define adc_voltage(x) (adc_reading[x] * 1200/adc_reading[8]) 
+/* return vbatt voltage in mV */
+#define adc_vbatt 4095 * 1200/adc_reading[8] + ADC_VBATT_TRIM
+
 void ADC_flush(void);
 uint16_t ADC_READ(void);
 void read_scanners(void);
diff --git a/tests/adc.c b/tests/adc.c
index 28a98ce75..dea333962 100644
--- a/tests/adc.c
+++ b/tests/adc.c
@@ -52,12 +52,17 @@ int main(void)
 
 	printf("\x1B[2J"); // clear screen
 
+	for (c=0; c<=7; c++) {
+		adc_setup_chan(c);
+	}
+
 	for(;;) {
 		printf("\x1B[H"); // cursor home
 		printf("# Value\r\n");
 		for (c=0; c<NUM_ADC_CHAN; c++) {
 			adc_service();
-			printf("%u %04u\r\n", c, adc_reading[c]);
+			printf("%u %04u %04u mV\r\n", c, adc_reading[c], adc_voltage(c));
 		}
+		printf("vbatt: %04u mV", adc_vbatt);
 	}
 }