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hzeller / rpi-rgb-led-matrix

Controlling up to three chains of 64x64, 32x32, 16x32 or similar RGB LED displays using Raspberry Pi GPIO
GNU General Public License v2.0
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rPi4 needs --led-slowdown-gpio=2, should it be a default? #996

Open marcmerlin opened 4 years ago

marcmerlin commented 4 years ago

~/rpi-rgb-led-matrix3/examples-api-use/demo --led-gpio-mapping=regular --led-rows=64 --led-cols=128 --led-row-addr-type=0 --led-chain=1 --led-show-refresh --led-slowdown-gpio=1 --led-parallel=3 --led-pwm-dither-bits=1 --led-pwm-lsb-nanoseconds=50 --led-pwm-bits=7 --led-panel-type=FM6126A -D0

did not give me a workable display (670.8Hz), this is using the code built on rPi3, which was a bit faster than the same code rebuilt on rPi4 (true for --led-slowdown-gpio=1 but with --led-slowdown-gpio=2 then the rPI4 rebuilt code is actually faster)

IMG_20200305_091221

marcmerlin commented 4 years ago

Same command with the same code, but rebuilt natively on rPI4, is actually slower ( 583.1Hz ) and doesn't work at all with --led-slowdown-gpio=1

IMG_20200305_091103

marcmerlin commented 4 years ago

With --led-slowdown-gpio=2, it works without issues. As a bonus, ABCDE panels (128x64 in led-parallel=3), work a bit faster than on rPI3 (411.7Hz vs 373.3Hz) IMG_20200305_092445

hzeller commented 4 years ago

yes, i am considering making the default dependent on the detected pi.