esp8266_pwm.patch

From 8364d03d4c8cf4fdcba6d24c968d73cc75455ccc Mon Sep 17 00:00:00 2001
From: Daniel Frejek <daniel.frejek@stusta.net>
Date: Fri, 16 Oct 2020 19:08:03 +0200
Subject: [PATCH] Use NMI for PWM

---
 ports/esp8266/esppwm.c | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/ports/esp8266/esppwm.c b/ports/esp8266/esppwm.c
index d5bcea9ac..7fcf56421 100644
--- a/ports/esp8266/esppwm.c
+++ b/ports/esp8266/esppwm.c
@@ -22,6 +22,8 @@
 #define PWM_DBG(...)
 // #define PWM_DBG(...) mp_printf(&mp_plat_print, __VA_ARGS__)
 
+#define PWM_INTR_NMI 1
+
 #define ICACHE_RAM_ATTR // __attribute__((section(".text")))
 
 #define PWM_CHANNEL 8
@@ -298,10 +300,14 @@ pwm_get_freq(uint8 channel) {
  * Parameters   : NONE
  * Returns      : NONE
 *******************************************************************************/
+#if PWM_INTR_NMI
+STATIC void ICACHE_RAM_ATTR
+pwm_tim1_intr_handler() {
+#else
 STATIC void ICACHE_RAM_ATTR
 pwm_tim1_intr_handler(void *dummy) {
     (void)dummy;
-
+#endif
     RTC_CLR_REG_MASK(FRC1_INT_ADDRESS, FRC1_INT_CLR_MASK);
 
     if (pwm_current_channel >= (*pwm_channel - 1)) {        // *pwm_channel may change outside
@@ -314,19 +320,15 @@ pwm_tim1_intr_handler(void *dummy) {
         pwm_single = pwm_single_toggle[pwm_toggle];
         pwm_channel = &pwm_channel_toggle[pwm_toggle];
 
-        gpio_output_set(pwm_single[*pwm_channel - 1].gpio_set,
-            pwm_single[*pwm_channel - 1].gpio_clear,
-            pwm_gpio,
-            0);
+        GPIO_REG_WRITE(GPIO_OUT_W1TS_ADDRESS, pwm_single[*pwm_channel - 1].gpio_set);
+        GPIO_REG_WRITE(GPIO_OUT_W1TC_ADDRESS, pwm_single[*pwm_channel - 1].gpio_clear);
 
         pwm_current_channel = 0;
 
         RTC_REG_WRITE(FRC1_LOAD_ADDRESS, pwm_single[pwm_current_channel].h_time);
     } else {
-        gpio_output_set(pwm_single[pwm_current_channel].gpio_set,
-            pwm_single[pwm_current_channel].gpio_clear,
-            pwm_gpio, 0);
-
+        GPIO_REG_WRITE(GPIO_OUT_W1TS_ADDRESS, pwm_single[pwm_current_channel].gpio_set);
+        GPIO_REG_WRITE(GPIO_OUT_W1TC_ADDRESS, pwm_single[pwm_current_channel].gpio_clear);
         pwm_current_channel++;
         RTC_REG_WRITE(FRC1_LOAD_ADDRESS, pwm_single[pwm_current_channel].h_time);
     }
@@ -357,7 +359,11 @@ pwm_init(void) {
     pwm_set_freq(500, 0);
     pwm_start();
 
+#if PWM_INTR_NMI
+    ETS_FRC_TIMER1_NMI_INTR_ATTACH(pwm_tim1_intr_handler);
+#else
     ETS_FRC_TIMER1_INTR_ATTACH(pwm_tim1_intr_handler, NULL);
+#endif
     TM1_EDGE_INT_ENABLE();
     ETS_FRC1_INTR_ENABLE();
 }
@@ -390,6 +396,7 @@ pwm_add(uint8_t pin_id, uint32_t pin_mux, uint32_t pin_func) {
             pwm_gpio |= (1 << pin_num[channel]);
             PIN_FUNC_SELECT(pin_mux, pin_func);
             GPIO_REG_WRITE(GPIO_PIN_ADDR(GPIO_ID_PIN(pin_num[channel])), GPIO_REG_READ(GPIO_PIN_ADDR(GPIO_ID_PIN(pin_num[channel]))) & (~GPIO_PIN_PAD_DRIVER_SET(GPIO_PAD_DRIVER_ENABLE)));  // disable open drain;
+            gpio_output_set(0, 0, pwm_gpio, 0);
             pwm_channel_num++;
             UNLOCK_PWM(critical);   // leave critical
             return channel;
-- 
2.28.0