From 413ff19ea8e0e5e09c0233225ffa8ad07b1233d6 Mon Sep 17 00:00:00 2001 From: Kevin O'Connor Date: Thu, 17 Apr 2025 13:06:22 -0400 Subject: [PATCH] neopixel: Add comments on timing Signed-off-by: Kevin O'Connor --- src/neopixel.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/src/neopixel.c b/src/neopixel.c index e7890a06..4e171658 100644 --- a/src/neopixel.c +++ b/src/neopixel.c @@ -1,6 +1,6 @@ // Support for bit-banging commands to WS2812 type "neopixel" LEDs // -// Copyright (C) 2019 Kevin O'Connor +// Copyright (C) 2019-2025 Kevin O'Connor // // This file may be distributed under the terms of the GNU GPLv3 license. @@ -74,8 +74,11 @@ neopixel_delay(neopixel_time_t start, neopixel_time_t ticks) #endif +// Minimum amount of time for a '1 bit' to be reliably detected #define PULSE_LONG_TICKS nsecs_to_ticks(650) -#define PULSE_SHORT_TICKS nsecs_to_ticks(200) +// Minimum amount of time for any level change to be reliably detected +#define EDGE_MIN_TICKS nsecs_to_ticks(200) +// Minimum average time needed to transmit each bit (two level changes) #define BIT_MIN_TICKS nsecs_to_ticks(1250) @@ -147,14 +150,14 @@ send_data(struct neopixel_s *n) gpio_out_toggle_noirq(pin); irq_enable(); - neopixel_delay(neopixel_get_time(), PULSE_SHORT_TICKS); + neopixel_delay(neopixel_get_time(), EDGE_MIN_TICKS); } else { // Short pulse neopixel_delay(last_start, BIT_MIN_TICKS); irq_disable(); neopixel_time_t start = neopixel_get_time(); gpio_out_toggle_noirq(pin); - neopixel_delay(start, PULSE_SHORT_TICKS); + neopixel_delay(start, EDGE_MIN_TICKS); gpio_out_toggle_noirq(pin); irq_enable();