get stuff ready fore rev4.2: remove ADC2 as Vbus reference (it sucked anyway), add DAC_nSHDN pin stuff

src/cli/dragonzap.c

@@ -8,16 +8,6 @@
 void cli_dragonzap_test(void);
 
 void cli_dragonzap_test(void) {
-	// TODO: test:
-	// * ADC0,1,2 input
-	//   -> ADC0,1: OK
-	//   -> ADC2: ≃0xB80 is 5.04V; not ≃0xC38?
-	//            2.48V measured at ADC2 pin...
-	// * DAC control
-	// * MAX4619 control (enable, switch)
-	// * crowbar 1,2 control
-	// * NXS0108 functionality
-
 	zap_init_default();
 	zap_dac_set_enable(zap_dac_a | zap_dac_b);
 	zap_dac_set_mulx2(zap_dac_a | zap_dac_b);
@@ -29,13 +19,13 @@ void cli_dragonzap_test(void) {
 	}
 
 	while (true) {
-		uint16_t adcv[3];
-		for (int i = 0; i < 3; ++i) {
+		uint16_t adcv[2];
+		for (int i = 0; i < 2; ++i) {
 			adcv[i] = zap_adc_read(i);
 		}
-		uint32_t vbus = zap_adc_get_vbus();
-		float vbusf = vbus / (float)0x10000;
-		printf("ADC: 0x%04x, 0x%04x, 0x%04x = %.2f\n", adcv[0], adcv[1], adcv[2], vbusf);
+		/*uint32_t vbus = zap_adc_get_vbus();
+		float vbusf = vbus / (float)0x10000;*/
+		printf("ADC: 0x%04x, 0x%04x"/*", 0x%04x = %.2f"*/"\n", adcv[0], adcv[1]/*, adcv[2], vbusf*/);
 
 		zap_dac_set_a(adcv[0]);
 		zap_dac_set_b(adcv[1]);

src/zap/zap.h

@@ -23,7 +23,7 @@ enum zap_component {
 static inline void zap_init(enum zap_component zc) {
 	if (zc & zap_adc) zap_adc_init();
 	if (zc & zap_crowbar) zap_crowbar_init();
-	if (zc & zap_dac) zap_dac_init();
+	if (zc & zap_dac) zap_dac_init(false);
 	if (zc & zap_gpio) zap_gpio_init(false, true);
 	if (zc & zap_max4619) zap_max_init(false, false);
 	if (zc & zap_picoemp) zap_picoemp_init();

src/zap/zap_adc.c

@@ -12,11 +12,11 @@ void zap_adc_init(void) {
 
 	adc_gpio_init(ZAP_ADC_A);
 	adc_gpio_init(ZAP_ADC_B);
-	adc_gpio_init(ZAP_ADC_REF);
+	//adc_gpio_init(ZAP_ADC_REF);
 }
 
 uint16_t zap_adc_read(int idx) {
-	if (idx < 0 || idx >= 3) return 0xf000;
+	if (idx < 0 || idx >= 2/*3*/) return 0xf000;
 
 	adc_select_input(idx);
 	return adc_read();

src/zap/zap_adc.h

@@ -16,16 +16,16 @@ static inline uint16_t zap_adc_read_b(void) { return zap_adc_read(1); }
 // sadly uuuh in practice it's 'a bit' noisy, assuming Vbus = 5V is
 // often more reliable than hand-tuning with this value, due to ADC
 // inaccuracies, mismatch between R500 and R501, and so on...
-static inline uint32_t zap_adc_get_vbus(void) {
-	// Vbus value, 0x0fff = 3V3
-	// (ADC2 value is Vbus divided down by 2)
-	uint32_t vbus = (zap_adc_read(2) + 0x57/*hacky offset correction*/) * 2;
-
-	// shouldn't overflow
-	uint32_t vbusf = (vbus * (uint32_t)(3.3f * 0x10000)) / 0xfff;
-
-	return vbusf;
-}
+//static inline uint32_t zap_adc_get_vbus(void) {
+//	// Vbus value, 0x0fff = 3V3
+//	// (ADC2 value is Vbus divided down by 2)
+//	uint32_t vbus = (zap_adc_read(2) + 0x57/*hacky offset correction*/) * 2;
+//
+//	// shouldn't overflow
+//	uint32_t vbusf = (vbus * (uint32_t)(3.3f * 0x10000)) / 0xfff;
+//
+//	return vbusf;
+//}
 
 #endif
 

src/zap/zap_dac.c

@@ -13,19 +13,22 @@
 static enum zap_dac_ch gain, enable;
 static uint16_t va, vb;
 
-void zap_dac_init(void) {
+void zap_dac_init(bool shdn) {
 	spi_init(ZAP_DAC_SPI, 1*1000*1000); // TODO: can we go higher?
 	spi_set_format(ZAP_DAC_SPI, 16, SPI_CPOL_0, SPI_CPHA_0, SPI_MSB_FIRST);
 
 	gpio_put(ZAP_DAC_NLATCH, true);
 	gpio_put(ZAP_DAC_CS    , true);
+	//gpio_put(ZAP_DAC_NSHDN , !shdn);
 	gpio_set_dir(ZAP_DAC_NLATCH, GPIO_OUT);
 	gpio_set_dir(ZAP_DAC_CS    , GPIO_OUT);
+	//gpio_set_dir(ZAP_DAC_NSHDN , GPIO_OUT);
 
 	gpio_set_function(ZAP_DAC_SCLK  , GPIO_FUNC_SPI);
 	gpio_set_function(ZAP_DAC_TX    , GPIO_FUNC_SPI);
 	gpio_set_function(ZAP_DAC_NLATCH, GPIO_FUNC_SIO);
 	gpio_set_function(ZAP_DAC_CS    , GPIO_FUNC_SIO);
+	//gpio_set_function(ZAP_DAC_NSHDN , GPIO_FUNC_SIO);
 
 	enable = 0;
 	gain = 3; // 1x for both
@@ -34,9 +37,15 @@ void zap_dac_init(void) {
 }
 
 static void zap_flush(enum zap_dac_ch ch) {
+	// buffer is always enabled (in MCP49x2 case, doesn't exist in MCP48x2):
+	// limited BW isn't really an issue (we use the MAX4619 for that anyway),
+	// and output swing is also limited by the output buffer which has the same
+	// limitation. so, shrug
+
 	if (ch & zap_dac_a) {
 		uint16_t v = va;
 		v |= 0x8000*0; // channel A
+		v |= 0x4000; // buffered (MCP49x2, don't care on 48x2)
 		if (gain & zap_dac_a) v |= 0x2000;
 		if (enable & zap_dac_a) v |= 0x1000;
 
@@ -49,6 +58,7 @@ static void zap_flush(enum zap_dac_ch ch) {
 	if (ch & zap_dac_b) {
 		uint16_t v = vb;
 		v |= 0x8000*1; // channel B
+		v |= 0x4000; // buffered (MCP49x2, don't care on 48x2)
 		if (gain & zap_dac_b) v |= 0x2000;
 		if (enable & zap_dac_b) v |= 0x1000;
 

src/zap/zap_dac.h

@@ -5,12 +5,17 @@
 #include <stdint.h>
 #include <stdbool.h>
 
+#include <hardware/gpio.h>
+
+#include "zap_pinout.h"
+
 enum zap_dac_ch {
 	zap_dac_a = 1,
 	zap_dac_b = 2
 };
 
-void zap_dac_init(void);
+// "shdn": only relevant for MCP49x2
+void zap_dac_init(bool shdn);
 
 enum zap_dac_ch zap_dac_get_enable(void);
 void zap_dac_set_enable(enum zap_dac_ch ch);
@@ -21,6 +26,11 @@ uint16_t zap_dac_get_b(void);
 void zap_dac_set_a(uint16_t a);
 void zap_dac_set_b(uint16_t b);
 
+// only relevant for MCP49x2
+static inline void zap_dac_set_shutdown(bool shdn) {
+	//gpio_put(ZAP_DAC_NSHDN, !shdn);
+}
+
 static inline void zap_dac_set(uint16_t a, uint16_t b) {
 	zap_dac_set_a(a);
 	zap_dac_set_b(b);

src/zap/zap_pinout.h

@@ -20,10 +20,11 @@
 #define ZAP_DAC_SCLK   18
 #define ZAP_DAC_TX     19
 #define ZAP_DAC_CS     20
+#define ZAP_DAC_NSHDN  28
 
 #define ZAP_ADC_A      26
 #define ZAP_ADC_B      27
-#define ZAP_ADC_REF    28
+/*#define ZAP_ADC_REF    28*/
 
 #define ZAP_PICOEMP_PWM 14
 #define ZAP_PICOEMP_CHG 15