ArmMiteF4 BITBANG BITSTREAM Operation


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Volhout
Guru

Joined: 05/03/2018
Location: Netherlands
Posts: 3691
Posted: 01:39pm 21 Mar 2024      

Phil,

There is more that is weird.
The bursts are 42 cycles of 13us = 546us (not exacly 562, but close)
The pauses between the bursts must be 562us (logic 0) -or- 1686us (logic 1).

Look at both scope plots. Either the burst timing is wrong, or the pause timing is wrong. Visually there is simply too much burst visible.
Checkif a single cycle is 13+13=26us. It feels the burst is 800us, in which case 13us is more 20us, 38kHz is 25kHz.

Volhout

P.S.... this feels like a job for PIO. Shift the 32 bit NEC value in FIFO, and let PIO do it's job. But I guess this is for the F4. No PIO.

Volhout
Edited 2024-03-21 23:47 by Volhout