diff options
| author | Scott Shawcroft <scott.shawcroft@gmail.com> | 2017-11-06 16:28:52 -0800 |
|---|---|---|
| committer | Scott Shawcroft <scott.shawcroft@gmail.com> | 2017-11-06 16:30:11 -0800 |
| commit | a8ee0012d715182eeb608f867be0403cd96137d1 (patch) | |
| tree | b562b09d1078072aa51900cd9e8bbff4e2db9028 | |
| parent | e2867eb4e9a2c4aea206a3fd985360c68a3da169 (diff) | |
atmel-samd: Enable -Os for SAMD51 and update neopixel accordingly.
| -rw-r--r-- | ports/atmel-samd/Makefile | 2 | ||||
| -rw-r--r-- | ports/atmel-samd/common-hal/neopixel_write/__init__.c | 31 |
2 files changed, 16 insertions, 17 deletions
diff --git a/ports/atmel-samd/Makefile b/ports/atmel-samd/Makefile index 2546c416d..8be3ce327 100644 --- a/ports/atmel-samd/Makefile +++ b/ports/atmel-samd/Makefile @@ -85,7 +85,7 @@ CFLAGS = -Os -DNDEBUG endif ifeq ($(CHIP_FAMILY), samd51) -CFLAGS = -O2 -DNDEBUG +CFLAGS = -Os -DNDEBUG endif #Debugging/Optimization diff --git a/ports/atmel-samd/common-hal/neopixel_write/__init__.c b/ports/atmel-samd/common-hal/neopixel_write/__init__.c index d9f7da6a8..6133415f4 100644 --- a/ports/atmel-samd/common-hal/neopixel_write/__init__.c +++ b/ports/atmel-samd/common-hal/neopixel_write/__init__.c @@ -32,18 +32,17 @@ #include "tick.h" #ifdef SAMD51 -static inline void delay_cycles(uint8_t cycles) { - uint32_t start = SysTick->VAL; - uint32_t stop = start - cycles; - if (start < cycles) { - stop = 0xffffff + start - cycles; - while (SysTick->VAL < start || SysTick->VAL > stop) {} - } else { - // Make sure the systick value is between start and stop in case it - // wraps around before we read its value less than stop. - while (SysTick->VAL > stop && SysTick->VAL <= start) {} +// This magical macro makes sure the delay isn't optimized out and is the +// minimal three instructions. +#define delay_cycles(cycles) \ +{ \ + uint32_t t; \ + asm volatile ( \ + "movs %[t], %[c]\n\t" \ + "loop%=:\n\t" \ + "subs %[t], #1\n\t" \ + "bne.n loop%=" : [t] "=r"(t) : [c] "I" (cycles)); \ } -} #endif uint64_t next_start_tick_ms = 0; @@ -88,7 +87,7 @@ void common_hal_neopixel_write(const digitalio_digitalinout_obj_t* digitalinout, asm("nop; nop;"); #endif #ifdef SAMD51 - delay_cycles(18); + delay_cycles(3); #endif if(p & bitMask) { // This is the high delay unique to a one bit. @@ -97,7 +96,7 @@ void common_hal_neopixel_write(const digitalio_digitalinout_obj_t* digitalinout, asm("nop; nop; nop; nop; nop; nop; nop;"); #endif #ifdef SAMD51 - delay_cycles(25); + delay_cycles(11); #endif *clr = pinMask; } else { @@ -108,7 +107,7 @@ void common_hal_neopixel_write(const digitalio_digitalinout_obj_t* digitalinout, asm("nop; nop;"); #endif #ifdef SAMD51 - delay_cycles(25); + delay_cycles(3); #endif } if((bitMask >>= 1) != 0) { @@ -119,7 +118,7 @@ void common_hal_neopixel_write(const digitalio_digitalinout_obj_t* digitalinout, asm("nop; nop; nop; nop; nop;"); #endif #ifdef SAMD51 - delay_cycles(44); + delay_cycles(20); #endif } else { if(ptr >= end) break; @@ -130,7 +129,7 @@ void common_hal_neopixel_write(const digitalio_digitalinout_obj_t* digitalinout, // above operations take. // For the SK6812 its 0.6us +- 0.15us #ifdef SAMD51 - delay_cycles(50); + delay_cycles(15); #endif } } |