Initial HW PWM (Delta-Sigma) (#609)

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_ */