ESP32 force bitbang in IRAM (#446)

* ESP32 force bitbang in IRAM * Split send_pixels into inverted and non-inverted Co-authored-by: Stephan Hadinger <stephan.hadinger@gmail.com>
2021-03-13 15:42:01 -08:00
parent dccf8d5709
commit f16a39f7af
2 changed files with 163 additions and 85 deletions
@@ -0,0 +1,154 @@
+/*-------------------------------------------------------------------------
+NeoPixel library helper functions for Esp8266 and Esp32
+
+Written by Michael C. Miller.
+
+I invest time and resources providing this open source code,
+please support me by dontating (see https://github.com/Makuna/NeoPixelBus)
+
+-------------------------------------------------------------------------
+This file is part of the Makuna/NeoPixelBus library.
+
+NeoPixelBus is free software: you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as
+published by the Free Software Foundation, either version 3 of
+the License, or (at your option) any later version.
+
+NeoPixelBus is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public
+License along with NeoPixel.  If not, see
+<http://www.gnu.org/licenses/>.
+-------------------------------------------------------------------------*/
+
+#if defined(ARDUINO_ARCH_ESP8266) || defined(ARDUINO_ARCH_ESP32)
+
+#include <Arduino.h>
+
+static inline uint32_t getCycleCount(void)
+{
+    uint32_t ccount;
+    __asm__ __volatile__("rsr %0,ccount":"=a" (ccount));
+    return ccount;
+}
+
+void ICACHE_RAM_ATTR NeoEspBitBangBase_send_pixels(uint8_t* pixels, uint8_t* end, uint8_t pin, uint32_t t0h, uint32_t t1h, uint32_t period)
+{
+    const uint32_t pinRegister = _BV(pin);
+    uint8_t mask = 0x80;
+    uint8_t subpix = *pixels++;
+    uint32_t cyclesStart = 0; // trigger emediately
+    uint32_t cyclesNext = 0;
+
+    for (;;)
+    {
+        // do the checks here while we are waiting on time to pass
+        uint32_t cyclesBit = t0h;
+        if (subpix & mask)
+        {
+            cyclesBit = t1h;
+        }
+
+        // after we have done as much work as needed for this next bit
+        // now wait for the HIGH
+        while (((cyclesStart = getCycleCount()) - cyclesNext) < period);
+
+        // set pin state
+#if defined(ARDUINO_ARCH_ESP32)
+        GPIO.out_w1ts = pinRegister;
+#else
+        GPIO_REG_WRITE(GPIO_OUT_W1TS_ADDRESS, pinRegister);
+#endif
+
+        // wait for the LOW
+        while ((getCycleCount() - cyclesStart) < cyclesBit);
+
+        // reset pin start
+#if defined(ARDUINO_ARCH_ESP32)
+        GPIO.out_w1tc = pinRegister;
+#else
+        GPIO_REG_WRITE(GPIO_OUT_W1TC_ADDRESS, pinRegister);
+#endif
+
+        cyclesNext = cyclesStart;
+
+        // next bit
+        mask >>= 1;
+        if (mask == 0)
+        {
+            // no more bits to send in this byte
+            // check for another byte
+            if (pixels >= end)
+            {
+                // no more bytes to send so stop
+                break;
+            }
+            // reset mask to first bit and get the next byte
+            mask = 0x80;
+            subpix = *pixels++;
+        }
+    }
+}
+
+void ICACHE_RAM_ATTR NeoEspBitBangBase_send_pixels_inv(uint8_t* pixels, uint8_t* end, uint8_t pin, uint32_t t0h, uint32_t t1h, uint32_t period)
+{
+    const uint32_t pinRegister = _BV(pin);
+    uint8_t mask = 0x80;
+    uint8_t subpix = *pixels++;
+    uint32_t cyclesStart = 0; // trigger emediately
+    uint32_t cyclesNext = 0;
+
+    for (;;)
+    {
+        // do the checks here while we are waiting on time to pass
+        uint32_t cyclesBit = t0h;
+        if (subpix & mask)
+        {
+            cyclesBit = t1h;
+        }
+
+        // after we have done as much work as needed for this next bit
+        // now wait for the HIGH
+        while (((cyclesStart = getCycleCount()) - cyclesNext) < period);
+
+        // set pin state
+#if defined(ARDUINO_ARCH_ESP32)
+        GPIO.out_w1tc = pinRegister;
+#else
+        GPIO_REG_WRITE(GPIO_OUT_W1TC_ADDRESS, pinRegister);
+#endif
+
+        // wait for the LOW
+        while ((getCycleCount() - cyclesStart) < cyclesBit);
+
+        // reset pin start
+#if defined(ARDUINO_ARCH_ESP32)
+        GPIO.out_w1ts = pinRegister;
+#else
+        GPIO_REG_WRITE(GPIO_OUT_W1TS_ADDRESS, pinRegister);
+#endif
+
+        cyclesNext = cyclesStart;
+
+        // next bit
+        mask >>= 1;
+        if (mask == 0)
+        {
+            // no more bits to send in this byte
+            // check for another byte
+            if (pixels >= end)
+            {
+                // no more bytes to send so stop
+                break;
+            }
+            // reset mask to first bit and get the next byte
+            mask = 0x80;
+            subpix = *pixels++;
+        }
+    }
+}
+
+#endif