test and adjust NeoPixel timings on multiple products
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Dan Halbert
parent
0642917cf7
commit
4eeaf41edc
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@ -46,6 +46,9 @@ __attribute__((naked,noinline,aligned(16)))
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static void neopixel_send_buffer_core(volatile uint32_t *clraddr, uint32_t pinMask,
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const uint8_t *ptr, int numBytes);
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// The SAMD21 timing loop durations below are approximate,
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// because the other instructions take significant time.
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static void neopixel_send_buffer_core(volatile uint32_t *clraddr, uint32_t pinMask,
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const uint8_t *ptr, int numBytes) {
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asm volatile (" push {r4, r5, r6, lr};"
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@ -54,25 +57,28 @@ static void neopixel_send_buffer_core(volatile uint32_t *clraddr, uint32_t pinMa
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" ldrb r5, [r2, #0];" // r5 := *ptr
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" add r2, #1;" // ptr++
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" movs r4, #128;" // r4-mask, 0x80
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"loopBit:"
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" str r1, [r0, #4];" // set
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#ifdef SAMD21
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" movs r6, #3; d2: sub r6, #1; bne d2;" // delay 3
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" movs r6, #2; d2: sub r6, #1; bne d2;" // 248 ns high (entire T0H or start T1H)
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#endif
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#ifdef SAM_D5X_E5X
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" movs r6, #16; d2: subs r6, #1; bne d2;" // delay 3
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" movs r6, #11; d2: subs r6, #1; bne d2;" // 300 ns high (entire T0H or start T1H)
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#endif
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" tst r4, r5;" // mask&r5
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" bne skipclr;"
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" str r1, [r0, #0];" // clr
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"skipclr:"
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#ifdef SAMD21
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" movs r6, #6; d0: sub r6, #1; bne d0;" // delay 6
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" movs r6, #7; d0: sub r6, #1; bne d0;" // 772 ns low or high (start T0L or end T1H)
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#endif
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#ifdef SAM_D5X_E5X
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" movs r6, #16; d0: subs r6, #1; bne d0;" // delay 6
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" movs r6, #15; d0: subs r6, #1; bne d0;" // 388 ns low or high (start T0L or end T1H)
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#endif
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" str r1, [r0, #0];" // clr (possibly again, doesn't matter)
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#ifdef SAMD21
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" asr r4, r4, #1;" // mask >>= 1
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#endif
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@ -82,15 +88,20 @@ static void neopixel_send_buffer_core(volatile uint32_t *clraddr, uint32_t pinMa
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" beq nextbyte;"
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" uxtb r4, r4;"
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#ifdef SAMD21
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" movs r6, #2; d1: sub r6, #1; bne d1;" // delay 2
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" movs r6, #5; d1: sub r6, #1; bne d1;" // 496 ns (end TOL or entire T1L)
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#endif
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#ifdef SAM_D5X_E5X
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" movs r6, #15; d1: subs r6, #1; bne d1;" // delay 2
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" movs r6, #20; d1: subs r6, #1; bne d1;" // 548 ns (end TOL or entire T1L)
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#endif
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" b loopBit;"
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"nextbyte:"
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#ifdef SAM_D5X_E5X
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" movs r6, #12; d3: subs r6, #1; bne d3;" // delay 2
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#ifdef SAMD21
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" movs r6, #1; d3: sub r6, #1; bne d3;" // 60 ns (end TOL or entire T1L)
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// other instructions add more delay
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#endif
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#ifdef SAM_D5X_E5X
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" movs r6, #18; d3: subs r6, #1; bne d3;" // extra for 936 ns total (byte end T0L or entire T1L)
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#endif
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" cmp r2, r3;"
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" bcs neopixel_stop;"
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@ -47,11 +47,11 @@
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#include "components/driver/include/driver/rmt.h"
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#include "peripherals/rmt.h"
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// 416 ns is 1/3 of the 1250ns period of a 800khz signal.
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#define WS2812_T0H_NS (416)
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#define WS2812_T0L_NS (416 * 2)
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#define WS2812_T1H_NS (416 * 2)
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#define WS2812_T1L_NS (416)
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// Use closer to WS2812-style timings instead of WS2812B, to accommodate more varieties.
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#define WS2812_T0H_NS (316)
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#define WS2812_T0L_NS (316 * 3)
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#define WS2812_T1H_NS (700)
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#define WS2812_T1L_NS (564)
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static uint32_t ws2812_t0h_ticks = 0;
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static uint32_t ws2812_t1h_ticks = 0;
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@ -53,13 +53,16 @@
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// The PWM starts the duty cycle in LOW. To start with HIGH we
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// need to set the 15th bit on each register.
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// *** CircuitPython: Use WS2812 for all, works with https://adafru.it/5225 and everything else
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// ***
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// WS2812 (rev A) timing is 0.35 and 0.7us
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// #define MAGIC_T0H 5UL | (0x8000) // 0.3125us
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// #define MAGIC_T1H 12UL | (0x8000) // 0.75us
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#define MAGIC_T0H 5UL | (0x8000) // 0.3125us
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#define MAGIC_T1H 12UL | (0x8000) // 0.75us
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// WS2812B (rev B) timing is 0.4 and 0.8 us
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#define MAGIC_T0H 6UL | (0x8000) // 0.375us
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#define MAGIC_T1H 13UL | (0x8000) // 0.8125us
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// #define MAGIC_T0H 6UL | (0x8000) // 0.375us
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// #define MAGIC_T1H 13UL | (0x8000) // 0.8125us
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#define CTOPVAL 20UL // 1.25us
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// ---------- END Constants for the EasyDMA implementation -------------
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@ -35,23 +35,23 @@
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uint64_t next_start_raw_ticks = 0;
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// NeoPixels are 800khz bit streams. Zeroes are 1/3 duty cycle (~416ns) and ones
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// are 2/3 duty cycle (~833ns). Each of the instructions below take 1/3 duty
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// NeoPixels are 800khz bit streams. We are choosing zeros as <312ns hi, 936 lo> and ones
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// and ones as <700 ns hi, 556 ns lo>.
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// cycle. The first two instructions always run while only one of the two final
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// instructions run per bit. We start with the low period because it can be
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// longer than 1/3 period while waiting for more data.
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// longer while waiting for more data.
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const uint16_t neopixel_program[] = {
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// bitloop:
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// out x 1 side 0 [1]; Side-set still takes place before instruction stalls
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0x6121,
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// jmp !x do_zero side 1 [1]; Branch on the bit we shifted out after 1/3 duty delay. Positive pulse
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0x1123,
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// out x 1 side 0 [6]; Drive low. Side-set still takes place before instruction stalls.
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0x6621,
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// jmp !x do_zero side 1 [3]; Branch on the bit we shifted out previous delay. Drive high.
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0x1323,
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// do_one:
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// jmp bitloop side 1 [1]; Continue driving high, for a long pulse
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0x1100,
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// jmp bitloop side 1 [4]; Continue driving high, for a one (long pulse)
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0x1400,
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// do_zero:
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// nop side 0 [1]; Or drive low, for a short pulse
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0xa142
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// nop side 0 [4]; Or drive low, for a zero (short pulse)
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0xa442
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};
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void common_hal_neopixel_write(const digitalio_digitalinout_obj_t *digitalinout, uint8_t *pixels, uint32_t num_bytes) {
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@ -63,7 +63,7 @@ void common_hal_neopixel_write(const digitalio_digitalinout_obj_t *digitalinout,
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uint32_t pins_we_use = 1 << digitalinout->pin->number;
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bool ok = rp2pio_statemachine_construct(&state_machine,
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neopixel_program, sizeof(neopixel_program) / sizeof(neopixel_program[0]),
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800000 * 6, // 800 khz * 6 cycles per bit
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12800000, // MHz, to get about appropriate sub-bit times in PIO program.
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NULL, 0, // init program
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NULL, 1, // out
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NULL, 1, // in
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@ -38,8 +38,8 @@ uint64_t next_start_raw_ticks = 0;
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// sysclock divisors
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#define MAGIC_800_INT 900000 // ~1.11 us -> 1.2 field
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#define MAGIC_800_T0H 2800000 // ~0.36 us -> 0.44 field
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#define MAGIC_800_T1H 1350000 // ~0.74 us -> 0.84 field
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#define MAGIC_800_T0H 3500000 // 300ns actual; 880 low
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#define MAGIC_800_T1H 1350000 // 768ns actual; 412 low
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#pragma GCC push_options
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#pragma GCC optimize ("Os")
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@ -32,6 +32,42 @@
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#include "shared-bindings/util.h"
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#include "supervisor/shared/translate.h"
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// RGB LED timing information:
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// From the WS2811 datasheet: high speed mode
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// - T0H 0 code,high voltage time 0.25 us +-150ns
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// - T1H 1 code,high voltage time 0.6 us +-150ns
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// - T0L 0 code,low voltage time 1.0 us +-150ns
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// - T1L 1 code,low voltage time 0.65 us +-150ns
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// - RES low voltage time Above 50us
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// From the SK6812 datasheet:
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// - T0H 0 code, high level time 0.3us +-0.15us
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// - T1H 1 code, high level time 0.6us +-0.15us
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// - T0L 0 code, low level time 0.9us +-0.15us
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// - T1L 1 code, low level time 0.6us +-0.15us
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// - Trst Reset code，low level time 80us
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// From the WS2812 datasheet:
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// - T0H 0 code, high voltage time 0.35us +-150ns
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// - T1H 1 code, high voltage time 0.7us +-150ns
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// - T0L 0 code, low voltage time 0.8us +-150ns
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// - T1L 1 code, low voltage time 0.6us +-150ns
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// - RES low voltage time Above 50us
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// From the WS28212B datasheet:
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// - T0H 0 code, high voltage time 0.4us +-150ns
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// - T1H 1 code, high voltage time 0.8us +-150ns
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// - T0L 0 code, low voltage time 0.85us +-150ns
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// - T1L 1 code, low voltage time 0.45us +-150ns
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// - RES low voltage time Above 50us
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// The timings used in various ports do not always follow the guidelines above.
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// In general, a zero bit is about 300ns high, 900ns low.
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// A one bit is about 700ns high, 500ns low.
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// But the ports vary based on implementation considerations; the proof is in the testing.
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// https://adafru.it/5225 is more sensitive to timing and should be included in testing.
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STATIC void check_for_deinit(digitalio_digitalinout_obj_t *self) {
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if (common_hal_digitalio_digitalinout_deinited(self)) {
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raise_deinited_error();
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