diff --git a/core/include/esp/gpio_regs.h b/core/include/esp/gpio_regs.h
index c5a446c..167a4d1 100644
--- a/core/include/esp/gpio_regs.h
+++ b/core/include/esp/gpio_regs.h
@@ -70,7 +70,7 @@ struct GPIO_REGS {
uint32_t volatile STATUS_SET; // 0x20
uint32_t volatile STATUS_CLEAR; // 0x24
uint32_t volatile CONF[16]; // 0x28 - 0x64
- uint32_t volatile PWM; // 0x68
+ uint32_t volatile DSM; // 0x68
uint32_t volatile RTC_CALIB; // 0x6c
uint32_t volatile RTC_CALIB_RESULT; // 0x70
};
@@ -117,9 +117,9 @@ _Static_assert(sizeof(struct GPIO_REGS) == 0x74, "GPIO_REGS is the wrong size");
* GPIO_CONF_OPEN_DRAIN does not appear to work on all pins.
*
*
- * GPIO_CONF_SOURCE_PWM (boolean)
- * When set, GPIO pin output will be connected to the sigma-delta PWM
- * generator (controlled by the GPIO.PWM register). When cleared, pin
+ * GPIO_CONF_SOURCE_DSM (boolean)
+ * When set, GPIO pin output will be connected to the sigma-delta
+ * generator (controlled by the GPIO.DSM register). When cleared, pin
* output will function as a normal GPIO output (controlled by the
* GPIO.OUT* registers).
*/
@@ -130,7 +130,7 @@ _Static_assert(sizeof(struct GPIO_REGS) == 0x74, "GPIO_REGS is the wrong size");
#define GPIO_CONF_INTTYPE_M 0x00000007
#define GPIO_CONF_INTTYPE_S 7
#define GPIO_CONF_OPEN_DRAIN BIT(2)
-#define GPIO_CONF_SOURCE_PWM BIT(0)
+#define GPIO_CONF_SOURCE_DSM BIT(0)
/* Valid values for the GPIO_CONF_INTTYPE field */
typedef enum {
@@ -142,13 +142,13 @@ typedef enum {
GPIO_INTTYPE_LEVEL_HIGH = 5,
} gpio_inttype_t;
-/* Details for PWM register */
+/* Details for DSM register */
-#define GPIO_PWM_ENABLE BIT(16)
-#define GPIO_PWM_PRESCALER_M 0x000000ff
-#define GPIO_PWM_PRESCALER_S 8
-#define GPIO_PWM_TARGET_M 0x000000ff
-#define GPIO_PWM_TARGET_S 0
+#define GPIO_DSM_ENABLE BIT(16)
+#define GPIO_DSM_PRESCALER_M 0x000000ff
+#define GPIO_DSM_PRESCALER_S 8
+#define GPIO_DSM_TARGET_M 0x000000ff
+#define GPIO_DSM_TARGET_S 0
/* Details for RTC_CALIB register */
diff --git a/examples/dsm_test/Makefile b/examples/dsm_test/Makefile
new file mode 100644
index 0000000..8438f41
--- /dev/null
+++ b/examples/dsm_test/Makefile
@@ -0,0 +1,4 @@
+# Simple makefile for simple example
+PROGRAM=dsm_test
+EXTRA_COMPONENTS = extras/dsm
+include ../../common.mk
diff --git a/examples/dsm_test/dsm_test.c b/examples/dsm_test/dsm_test.c
new file mode 100644
index 0000000..234a66b
--- /dev/null
+++ b/examples/dsm_test/dsm_test.c
@@ -0,0 +1,67 @@
+/* Very basic example to test the dsm library
+ * Led intensity from module will change over time.
+ *
+ * Part of esp-open-rtos
+ * Copyright (C) 2018 zaltora (https://github.com/Zaltora)
+ * BSD Licensed as described in the file LICENSE
+ */
+#include "espressif/esp_common.h"
+#include "esp/uart.h"
+#include "FreeRTOS.h"
+#include "task.h"
+#include "dsm.h"
+
+#define TEST_WITH_160MHZ (0)
+#define DSM_PIN (2)
+
+void task1(void *pvParameters)
+{
+ uint32_t const init_count = 0;
+ uint32_t count = init_count;
+ while(1)
+ {
+ vTaskDelay(100/portTICK_PERIOD_MS);
+ printf("Target set to %3u, ", count);
+ //Freq = (80,000,000/prescale) * (target / 256) HZ (0 < target < 128)
+ //Freq = (80,000,000/prescale) * ((256 - target) / 256) HZ (128 < target < 256)
+ if (count < 128)
+ {
+ printf("Freqency: %.1f Hz\r\n", (80000000.0/255.0 * (count/ 256.0)));
+ }
+ else
+ {
+ printf("Freqency: %.1f Hz\r\n", 80000000.0/255.0 * ((256.0-count)/ 256.0));
+ }
+ dsm_set_target(count);
+ count++;
+ if (count > UINT8_MAX)
+ count = init_count;
+ }
+}
+
+void user_init(void)
+{
+ uint8_t pins[1];
+ uart_set_baud(0, 115200);
+
+#if (TEST_WITH_160MHZ)
+ sdk_system_update_cpu_freq(160);
+#endif
+
+ printf("SDK version:%s\r\n", sdk_system_get_sdk_version());
+
+ pins[0] = DSM_PIN;
+
+ /* register pin to use with DSM */
+ dsm_init(1, pins);
+ /* Set prescale to FF to get a proper signal */
+ dsm_set_prescale(0xFF);
+ /* Target initial */
+ dsm_set_target(0);
+ /* start dsm to pin */
+ dsm_start();
+
+ printf("dsm start\r\n");
+
+ xTaskCreate(task1, "tsk1", 256, NULL, 2, NULL);
+}
diff --git a/extras/dsm/component.mk b/extras/dsm/component.mk
new file mode 100644
index 0000000..06e56b1
--- /dev/null
+++ b/extras/dsm/component.mk
@@ -0,0 +1,9 @@
+# Component makefile for extras/dsm
+
+INC_DIRS += $(ROOT)extras/dsm
+
+# args for passing into compile rule generation
+extras/dsm_INC_DIR = $(ROOT)extras/dsm
+extras/dsm_SRC_DIR = $(ROOT)extras/dsm
+
+$(eval $(call component_compile_rules,extras/dsm))
diff --git a/extras/dsm/dsm.c b/extras/dsm/dsm.c
new file mode 100644
index 0000000..dd54fc4
--- /dev/null
+++ b/extras/dsm/dsm.c
@@ -0,0 +1,111 @@
+/* Implementation of Delta-Sigma modulator support.
+ *
+ * Part of esp-open-rtos
+ * Copyright (C) 2018 ourairquality (https://github.com/ourairquality)
+ * Copyright (C) 2018 Zaltora (https://github.com/Zaltora)
+ * BSD Licensed as described in the file LICENSE
+ */
+#include "dsm.h"
+
+#include <espressif/esp_common.h>
+#include <esp8266.h>
+
+
+#if (DSM_DEBUG)
+#define debug(fmt, ...) printf("%s: " fmt "\n", "DSM", ## __VA_ARGS__)
+#else
+#define debug(fmt, ...)
+#endif
+
+typedef struct dsmInfoDefinition
+{
+ uint8_t running;
+ uint8_t preScale;
+ uint8_t target;
+ bool output;
+
+ /* private */
+ uint8_t usedPins;
+ uint8_t pins[8];
+} DSMInfo;
+
+static DSMInfo dsmInfo;
+
+void dsm_init(uint8_t npins, const uint8_t* pins)
+{
+ /* Assert number of pins is correct */
+ if (npins > MAX_DSM_PINS)
+ {
+ debug("Incorrect number of DSM pins (%d)\n", npins);
+ return;
+ }
+
+ /* Save pins information */
+ dsmInfo.usedPins = npins;
+
+ for (uint8_t i = 0 ; i < npins; ++i)
+ {
+ dsmInfo.pins[i] = pins[i];
+ /* configure GPIOs */
+ gpio_enable(pins[i], GPIO_OUTPUT);
+ }
+
+ /* Set output to LOW */
+ dsm_stop();
+
+ /* Flag not running */
+ dsmInfo.running = 0;
+}
+
+void dsm_set_prescale(uint8_t prescale)
+{
+ //TODO: Add a freq/prescale converter
+ dsmInfo.preScale = prescale;
+ debug("Set Prescale: %u",dsmInfo.preScale);
+}
+
+void dsm_set_target(uint8_t target)
+{
+ dsmInfo.target = target;
+ if (target == 0 || target == UINT8_MAX)
+ {
+ dsmInfo.output = (target == UINT8_MAX);
+ }
+ debug("Duty set at %u",dsmInfo.target);
+ if (dsmInfo.running)
+ {
+ dsm_start();
+ }
+}
+
+void dsm_start()
+{
+ if (dsmInfo.target > 0 && dsmInfo.target < UINT8_MAX)
+ {
+ for (uint8_t i = 0; i < dsmInfo.usedPins; ++i)
+ {
+ SET_MASK_BITS(GPIO.CONF[dsmInfo.pins[i]], GPIO_CONF_SOURCE_DSM);
+ }
+ GPIO.DSM = GPIO_DSM_ENABLE | (dsmInfo.preScale << 8) | dsmInfo.target;
+ }
+ else
+ {
+ for (uint8_t i = 0; i < dsmInfo.usedPins; ++i)
+ {
+ gpio_write(dsmInfo.pins[i], dsmInfo.output );
+ }
+ }
+ debug("start");
+ dsmInfo.running = 1;
+}
+
+void dsm_stop()
+{
+ for (uint8_t i = 0; i < dsmInfo.usedPins; ++i)
+ {
+ CLEAR_MASK_BITS(GPIO.CONF[dsmInfo.pins[i]], GPIO_CONF_SOURCE_DSM);
+ gpio_write(dsmInfo.pins[i], false);
+ }
+ debug("stop");
+ dsmInfo.running = 0;
+}
diff --git a/extras/dsm/dsm.h b/extras/dsm/dsm.h
new file mode 100644
index 0000000..8190f7e
--- /dev/null
+++ b/extras/dsm/dsm.h
@@ -0,0 +1,36 @@
+/* Implementation of Delta-Sigma modulator support.
+ *
+ * Part of esp-open-rtos
+ * Copyright (C) 2018 ourairquality (https://github.com/ourairquality)
+ * Copyright (C) 2018 Zaltora (https://github.com/Zaltora)
+ * BSD Licensed as described in the file LICENSE
+ */
+#ifndef EXTRAS_DSM_H_
+#define EXTRAS_DSM_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+
+#define MAX_DSM_PINS (8)
+#define DSM_DEBUG (0)
+
+/*
+ * Freq = (80,000,000/prescale) * (target / 256) HZ (0 < target < 128)
+ * Freq = (80,000,000/prescale) * ((256 - target) / 256) HZ (128 < target < 256)
+ */
+
+void dsm_init(uint8_t npins, const uint8_t* pins);
+void dsm_set_prescale(uint8_t prescale);
+void dsm_set_target(uint8_t target);
+
+void dsm_start();
+void dsm_stop();
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* EXTRAS_DSM_H_ */