esp8266: Add APA102 serial individually controllable LEDs support.

APA102 is a new "smart LED", similar to WS2812 aka "Neopixel".

docs/esp8266/quickref.rst

@@ -271,6 +271,26 @@ For low-level driving of a NeoPixel::
     import esp
     esp.neopixel_write(pin, grb_buf, is800khz)
 
+APA102 driver
+-------------
+
+Use the ``apa102`` module::
+
+    from machine import Pin
+    from apa102 import APA102
+
+    clock = Pin(14, Pin.OUT)     # set GPIO14 to output to drive the clock
+    data = Pin(13, Pin.OUT)      # set GPIO13 to output to drive the data
+    apa = APA102(clock, data, 8) # create APA102 driver on the clock and the data pin for 8 pixels
+    apa[0] = (255, 255, 255, 31) # set the first pixel to white with a maximum brightness of 31
+    apa.write()                  # write data to all pixels
+    r, g, b, brightness = apa[0] # get first pixel colour
+
+For low-level driving of an APA102::
+
+    import esp
+    esp.apa102_write(clock_pin, data_pin, rgbi_buf)
+
 WebREPL (web browser interactive prompt)
 ----------------------------------------
 

esp8266/Makefile

@@ -65,6 +65,7 @@ SRC_C = \
 	esppwm.c \
 	esponewire.c \
 	espneopixel.c \
+	espapa102.c \
 	intr.c \
 	modpyb.c \
 	modpybpin.c \

esp8266/espapa102.c

+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2016 Robert Foss, Daniel Busch
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <stdio.h>
+#include "c_types.h"
+#include "eagle_soc.h"
+#include "user_interface.h"
+#include "espapa102.h"
+
+#define NOP asm volatile(" nop \n\t")
+
+static inline void _esp_apa102_send_byte(uint32_t clockPinMask, uint32_t dataPinMask, uint8_t byte) {
+    for (uint32_t i = 0; i < 8; i++) {
+        if (byte & 0x80) {
+            // set data pin high
+            GPIO_REG_WRITE(GPIO_OUT_W1TS_ADDRESS, dataPinMask);
+        } else {
+            // set data pin low
+            GPIO_REG_WRITE(GPIO_OUT_W1TC_ADDRESS, dataPinMask);
+        }
+
+        // set clock pin high
+        GPIO_REG_WRITE(GPIO_OUT_W1TS_ADDRESS, clockPinMask);
+        byte <<= 1;
+        NOP;
+        NOP;
+
+        // set clock pin low
+        GPIO_REG_WRITE(GPIO_OUT_W1TC_ADDRESS, clockPinMask);
+        NOP;
+        NOP;
+    }
+}
+
+static inline void _esp_apa102_send_colors(uint32_t clockPinMask, uint32_t dataPinMask, uint8_t *pixels, uint32_t numBytes) {
+    for (uint32_t i = 0; i < numBytes / 4; i++) {
+        _esp_apa102_send_byte(clockPinMask, dataPinMask, pixels[i * 4 + 3] | 0xE0);
+        _esp_apa102_send_byte(clockPinMask, dataPinMask, pixels[i * 4 + 2]);
+        _esp_apa102_send_byte(clockPinMask, dataPinMask, pixels[i * 4 + 1]);
+        _esp_apa102_send_byte(clockPinMask, dataPinMask, pixels[i * 4]);
+    }
+}
+
+static inline void _esp_apa102_start_frame(uint32_t clockPinMask, uint32_t dataPinMask) {
+    for (uint32_t i = 0; i < 4; i++) {
+        _esp_apa102_send_byte(clockPinMask, dataPinMask, 0x00);
+    }
+}
+
+static inline void _esp_apa102_append_additionial_cycles(uint32_t clockPinMask, uint32_t dataPinMask, uint32_t numBytes) {
+    GPIO_REG_WRITE(GPIO_OUT_W1TS_ADDRESS, dataPinMask);
+
+    // we need to write some more clock cycles, because each led
+    // delays the data by one edge after inverting the clock
+    for (uint32_t i = 0; i < numBytes / 8 + ((numBytes / 4) % 2); i++) {
+        GPIO_REG_WRITE(GPIO_OUT_W1TS_ADDRESS, clockPinMask);
+        NOP;
+        NOP;
+
+        GPIO_REG_WRITE(GPIO_OUT_W1TC_ADDRESS, clockPinMask);
+        NOP;
+        NOP;
+    }
+}
+
+static inline void _esp_apa102_end_frame(uint32_t clockPinMask, uint32_t dataPinMask) {
+    for (uint32_t i = 0; i < 4; i++) {
+        _esp_apa102_send_byte(clockPinMask, dataPinMask, 0xFF);
+    }
+}
+
+void esp_apa102_write(uint8_t clockPin, uint8_t dataPin, uint8_t *pixels, uint32_t numBytes) {
+    uint32_t clockPinMask, dataPinMask;
+
+    clockPinMask = 1 << clockPin;
+    dataPinMask = 1 << dataPin;
+
+    // start the frame
+    _esp_apa102_start_frame(clockPinMask, dataPinMask);
+
+    // write pixels
+    _esp_apa102_send_colors(clockPinMask, dataPinMask, pixels, numBytes);
+
+    // end the frame
+    _esp_apa102_append_additionial_cycles(clockPinMask, dataPinMask, numBytes);
+    _esp_apa102_end_frame(clockPinMask, dataPinMask);
+}

esp8266/espapa102.h

+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2016 Robert Foss, Daniel Busch
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+void esp_apa102_write(uint8_t clockPin, uint8_t dataPin, uint8_t *pixels, uint32_t numBytes);

esp8266/modesp.c

@@ -43,6 +43,7 @@
 #include "spi_flash.h"
 #include "mem.h"
 #include "espneopixel.h"
+#include "espapa102.h"
 #include "modpyb.h"
 
 #define MODESP_ESPCONN (0)
@@ -636,6 +637,16 @@ STATIC mp_obj_t esp_neopixel_write_(mp_obj_t pin, mp_obj_t buf, mp_obj_t is800k)
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_3(esp_neopixel_write_obj, esp_neopixel_write_);
 
+STATIC mp_obj_t esp_apa102_write_(mp_obj_t clockPin, mp_obj_t dataPin, mp_obj_t buf) {
+    mp_buffer_info_t bufinfo;
+    mp_get_buffer_raise(buf, &bufinfo, MP_BUFFER_READ);
+    esp_apa102_write(mp_obj_get_pin_obj(clockPin)->phys_port,
+        mp_obj_get_pin_obj(dataPin)->phys_port,
+        (uint8_t*)bufinfo.buf, bufinfo.len);
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_3(esp_apa102_write_obj, esp_apa102_write_);
+
 STATIC mp_obj_t esp_freemem() {
     return MP_OBJ_NEW_SMALL_INT(system_get_free_heap_size());
 }
@@ -679,6 +690,7 @@ STATIC const mp_map_elem_t esp_module_globals_table[] = {
     { MP_OBJ_NEW_QSTR(MP_QSTR_getaddrinfo), (mp_obj_t)&esp_getaddrinfo_obj },
     #endif
     { MP_OBJ_NEW_QSTR(MP_QSTR_neopixel_write), (mp_obj_t)&esp_neopixel_write_obj },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_apa102_write), (mp_obj_t)&esp_apa102_write_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR_freemem), (mp_obj_t)&esp_freemem_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR_meminfo), (mp_obj_t)&esp_meminfo_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR_info), (mp_obj_t)&pyb_info_obj }, // TODO delete/rename/move elsewhere

esp8266/scripts/apa102.py

+# APA102 driver for MicroPython on ESP8266
+# MIT license; Copyright (c) 2016 Robert Foss, Daniel Busch
+
+from esp import apa102_write
+
+class APA102:
+    def __init__(self, clock_pin, data_pin, n):
+        self.clock_pin = clock_pin
+        self.data_pin = data_pin
+        self.n = n
+        self.buf = bytearray(n * 4)
+
+        self.clock_pin.init(clock_pin.OUT)
+        self.data_pin.init(data_pin.OUT)
+
+    def __setitem__(self, index, val):
+        r, g, b, brightness = val
+        self.buf[index * 4] = r
+        self.buf[index * 4 + 1] = g
+        self.buf[index * 4 + 2] = b
+        self.buf[index * 4 + 3] = brightness
+
+    def __getitem__(self, index):
+        i = index * 4
+        return self.buf[i], self.buf[i + 1], self.buf[i + 2], self.buf[i + 3]
+
+    def write(self):
+        apa102_write(self.clock_pin, self.data_pin, self.buf)