diff options
| author | Sergey Vlasov <vsu@altlinux.ru> | 2021-02-09 00:33:04 +0300 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2021-02-09 08:33:04 +1100 |
| commit | 627ceebef3ed19eceba3642a830ffbf44f4a9e04 (patch) | |
| tree | 261ce414affa8c15f4973036153ec770553138ef | |
| parent | d2f204c1e3ef92d774feded0ba05a145c2d03cf7 (diff) | |
ws2812: Fix number of nops for AVR at 8 MHz (#9559)0.11.64
* ws2812: Fix number of nops for AVR at 8 MHz
When trying to calculate the number of nops for AVR running at 8 MHz,
the value of `w3` is expected to be negative; however, because `F_CPU`
is defined in tmk_core/avr.mk with the `UL` suffix, the preprocessor
performs its calculations using `unsigned long`, getting a very large
positive number instead of the expected negative number; this then
results in generating code with a huge number of nops. Fix the broken
calculations by performing a comparison before subtraction, so that the
unsigned number wraparound does not occur.
The keyboard which triggers the problem is `handwired/promethium`; the
buggy code silently compiles, but the resulting timings would be
completely wrong.
* ws2812: Clean up the code after the 8 MHz fix
Remove old code which was unsuccessfully trying to clamp negative w1, w2
and w3 values to 0, and set w1_nops, w2_nops and w3_nops directly.
| -rw-r--r-- | drivers/avr/ws2812.c | 38 |
1 files changed, 17 insertions, 21 deletions
diff --git a/drivers/avr/ws2812.c b/drivers/avr/ws2812.c index dd2ef89912..77c492cd4c 100644 --- a/drivers/avr/ws2812.c +++ b/drivers/avr/ws2812.c @@ -67,19 +67,27 @@ void ws2812_setleds(LED_TYPE *ledarray, uint16_t number_of_leds) { #define w_onecycles (((F_CPU / 1000) * w_onepulse + 500000) / 1000000) #define w_totalcycles (((F_CPU / 1000) * w_totalperiod + 500000) / 1000000) -// w1 - nops between rising edge and falling edge - low -#define w1 (w_zerocycles - w_fixedlow) -// w2 nops between fe low and fe high -#define w2 (w_onecycles - w_fixedhigh - w1) -// w3 nops to complete loop -#define w3 (w_totalcycles - w_fixedtotal - w1 - w2) - -#if w1 > 0 -# define w1_nops w1 +// w1_nops - nops between rising edge and falling edge - low +#if w_zerocycles >= w_fixedlow +# define w1_nops (w_zerocycles - w_fixedlow) #else # define w1_nops 0 #endif +// w2_nops - nops between fe low and fe high +#if w_onecycles >= (w_fixedhigh + w1_nops) +# define w2_nops (w_onecycles - w_fixedhigh - w1_nops) +#else +# define w2_nops 0 +#endif + +// w3_nops - nops to complete loop +#if w_totalcycles >= (w_fixedtotal + w1_nops + w2_nops) +# define w3_nops (w_totalcycles - w_fixedtotal - w1_nops - w2_nops) +#else +# define w3_nops 0 +#endif + // The only critical timing parameter is the minimum pulse length of the "0" // Warn or throw error if this timing can not be met with current F_CPU settings. #define w_lowtime ((w1_nops + w_fixedlow) * 1000000) / (F_CPU / 1000) @@ -90,18 +98,6 @@ void ws2812_setleds(LED_TYPE *ledarray, uint16_t number_of_leds) { # warning "Please consider a higher clockspeed, if possible" #endif -#if w2 > 0 -# define w2_nops w2 -#else -# define w2_nops 0 -#endif - -#if w3 > 0 -# define w3_nops w3 -#else -# define w3_nops 0 -#endif - #define w_nop1 "nop \n\t" #define w_nop2 "rjmp .+0 \n\t" #define w_nop4 w_nop2 w_nop2 |