Onboard neopixel led support

5 files changed, 168 insertions, 19 deletions

diff --git a/src/main.c b/src/main.c
index 25f6204..d73c530 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,12 +1,14 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
+#include <sys/types.h>
 
 #include "bsp/board.h"
 #include "tusb.h"
+#include "neopix.h"
 
 /* Blink pattern
- * - 250 ms	: device not mounted
+ * - 250 ms  : device not mounted
  * - 1000 ms : device mounted
  * - 2500 ms : device is suspended
  */
@@ -18,19 +20,20 @@ enum	{
 
 static uint32_t blink_interval_ms = BLINK_NOT_MOUNTED;
 
+static struct neopix onboard_led;
+
 void led_blinking_task(void);
 
-/*------------- MAIN -------------*/
 int main(void)
 {
 	board_init();
 
-	// init device stack on configured roothub port
+	neopix_init(&onboard_led, pio0, 0, 25);
+
 	tud_init(BOARD_TUD_RHPORT);
 
-	while (1)
-	{
-		tud_task(); // tinyusb device task
+	while (1) {
+		tud_task();
 		led_blinking_task();
 	}
 
@@ -78,7 +81,6 @@ void tud_resume_cb(void)
 uint16_t tud_hid_get_report_cb(uint8_t itf, uint8_t report_id,
 	hid_report_type_t report_type, uint8_t* buffer, uint16_t reqlen)
 {
-	// TODO not Implemented
 	(void) itf;
 	(void) report_id;
 	(void) report_type;
@@ -93,27 +95,24 @@ uint16_t tud_hid_get_report_cb(uint8_t itf, uint8_t report_id,
 void tud_hid_set_report_cb(uint8_t itf, uint8_t report_id,
 	hid_report_type_t report_type, uint8_t const* buffer, uint16_t bufsize)
 {
-	// This example doesn't use multiple report and report ID
 	(void) itf;
 	(void) report_id;
 	(void) report_type;
 
-	// echo back anything we received from host
 	tud_hid_report(0, buffer, bufsize);
 }
 
-//--------------------------------------------------------------------+
-// BLINKING TASK
-//--------------------------------------------------------------------+
-void led_blinking_task(void)
+void
+led_blinking_task(void)
 {
 	static uint32_t start_ms = 0;
-	static bool led_state = false;
+	static bool state = false;
 
-	// Blink every interval ms
-	if ( board_millis() - start_ms < blink_interval_ms) return; // not enough time
-	start_ms += blink_interval_ms;
+	if (board_millis() - start_ms < blink_interval_ms)
+		return;
+
+	neopix_put(&onboard_led, neopix_u32rgb(255 * state, 0, 0));
 
-	board_led_write(led_state);
-	led_state = 1 - led_state; // toggle
+	start_ms += blink_interval_ms;
+	state ^= true;
 }
diff --git a/src/neopix.c b/src/neopix.c
new file mode 100644
index 0000000..ddc78a3
--- /dev/null
+++ b/src/neopix.c
@@ -0,0 +1,22 @@
+#include "hardware/pio.h"
+
+#include "neopix.h"
+#include "ws2812.pio.h"
+
+void
+neopix_init(struct neopix *pix, PIO pio, uint sm, uint pin)
+{
+	uint offset;
+
+	pix->sm = sm;
+	pix->pio = pio;
+	pix->pin = pin;
+	offset = pio_add_program(pix->pio, &ws2812_program);
+	ws2812_program_init(pix->pio, pix->sm, offset,
+		pix->pin, 800000, false);
+}
+
+void
+neopix_put(struct neopix *pix, uint32_t rgb) {
+	pio_sm_put_blocking(pix->pio, pix->sm, rgb << 8u);
+}
diff --git a/src/neopix.h b/src/neopix.h
new file mode 100644
index 0000000..8b01038
--- /dev/null
+++ b/src/neopix.h
@@ -0,0 +1,22 @@
+#include "hardware/pio.h"
+#include "hardware/gpio.h"
+
+struct neopix {
+	PIO pio;
+	uint sm;
+	uint pin;
+};
+
+void neopix_init(struct neopix *pix, PIO pio, uint sm, uint pin);
+void neopix_put(struct neopix *pix, uint32_t rgb);
+
+inline uint32_t
+neopix_u32rgb(uint8_t r, uint8_t g, uint8_t b) {
+	uint32_t rgb;
+
+	rgb = ((uint32_t) r) << 8;
+	rgb |= ((uint32_t) g) << 16;
+	rgb |= ((uint32_t) b) << 0;
+
+	return rgb;
+}
diff --git a/src/ws2812.pio b/src/ws2812.pio
new file mode 100644
index 0000000..ae19a6b
--- /dev/null
+++ b/src/ws2812.pio
@@ -0,0 +1,48 @@
+;
+; Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
+;
+; SPDX-License-Identifier: BSD-3-Clause
+;
+
+.program ws2812
+.side_set 1
+
+.define public T1 2
+.define public T2 5
+.define public T3 3
+
+.lang_opt python sideset_init = pico.PIO.OUT_HIGH
+.lang_opt python out_init     = pico.PIO.OUT_HIGH
+.lang_opt python out_shiftdir = 1
+
+.wrap_target
+bitloop:
+    out x, 1       side 0 [T3 - 1] ; Side-set still takes place when instruction stalls
+    jmp !x do_zero side 1 [T1 - 1] ; Branch on the bit we shifted out. Positive pulse
+do_one:
+    jmp  bitloop   side 1 [T2 - 1] ; Continue driving high, for a long pulse
+do_zero:
+    nop            side 0 [T2 - 1] ; Or drive low, for a short pulse
+.wrap
+
+% c-sdk {
+#include "hardware/clocks.h"
+
+static inline void ws2812_program_init(PIO pio, uint sm, uint offset, uint pin, float freq, bool rgbw) {
+
+    pio_gpio_init(pio, pin);
+    pio_sm_set_consecutive_pindirs(pio, sm, pin, 1, true);
+
+    pio_sm_config c = ws2812_program_get_default_config(offset);
+    sm_config_set_sideset_pins(&c, pin);
+    sm_config_set_out_shift(&c, false, true, rgbw ? 32 : 24);
+    sm_config_set_fifo_join(&c, PIO_FIFO_JOIN_TX);
+
+    int cycles_per_bit = ws2812_T1 + ws2812_T2 + ws2812_T3;
+    float div = clock_get_hz(clk_sys) / (freq * cycles_per_bit);
+    sm_config_set_clkdiv(&c, div);
+
+    pio_sm_init(pio, sm, offset, &c);
+    pio_sm_set_enabled(pio, sm, true);
+}
+%}
diff --git a/src/ws2812.pio.h b/src/ws2812.pio.h
new file mode 100644
index 0000000..e95f7ea
--- /dev/null
+++ b/src/ws2812.pio.h
@@ -0,0 +1,58 @@
+// -------------------------------------------------- //
+// This file is autogenerated by pioasm; do not edit! //
+// -------------------------------------------------- //
+
+#if !PICO_NO_HARDWARE
+#include "hardware/pio.h"
+#endif
+
+// ------ //
+// ws2812 //
+// ------ //
+
+#define ws2812_wrap_target 0
+#define ws2812_wrap 3
+
+#define ws2812_T1 2
+#define ws2812_T2 5
+#define ws2812_T3 3
+
+static const uint16_t ws2812_program_instructions[] = {
+            //     .wrap_target
+    0x6221, //  0: out    x, 1            side 0 [2] 
+    0x1123, //  1: jmp    !x, 3           side 1 [1] 
+    0x1400, //  2: jmp    0               side 1 [4] 
+    0xa442, //  3: nop                    side 0 [4] 
+            //     .wrap
+};
+
+#if !PICO_NO_HARDWARE
+static const struct pio_program ws2812_program = {
+    .instructions = ws2812_program_instructions,
+    .length = 4,
+    .origin = -1,
+};
+
+static inline pio_sm_config ws2812_program_get_default_config(uint offset) {
+    pio_sm_config c = pio_get_default_sm_config();
+    sm_config_set_wrap(&c, offset + ws2812_wrap_target, offset + ws2812_wrap);
+    sm_config_set_sideset(&c, 1, false, false);
+    return c;
+}
+
+#include "hardware/clocks.h"
+static inline void ws2812_program_init(PIO pio, uint sm, uint offset, uint pin, float freq, bool rgbw) {
+    pio_gpio_init(pio, pin);
+    pio_sm_set_consecutive_pindirs(pio, sm, pin, 1, true);
+    pio_sm_config c = ws2812_program_get_default_config(offset);
+    sm_config_set_sideset_pins(&c, pin);
+    sm_config_set_out_shift(&c, false, true, rgbw ? 32 : 24);
+    sm_config_set_fifo_join(&c, PIO_FIFO_JOIN_TX);
+    int cycles_per_bit = ws2812_T1 + ws2812_T2 + ws2812_T3;
+    float div = ((float) clock_get_hz(clk_sys)) / (freq * (float) cycles_per_bit);
+    sm_config_set_clkdiv(&c, div);
+    pio_sm_init(pio, sm, offset, &c);
+    pio_sm_set_enabled(pio, sm, true);
+}
+
+#endif