[fpc-pascal] Reversing bit-order of byte
ludo.brands at free.fr
Thu May 3 10:45:01 CEST 2012
> I'm porting a driver, originally written in C, for an LCD to be used
> with an embedded arm-processor (STM32).
> The original driver uses SPI, my driver will use a USART in
> mode because the STM32 has no SPI for 9-bit. Unfortunately, the
> bit-order is reversed between SPI and USART transmission.
> Does anyone knows an efficient way to reverse bit-order of a byte for
> the arm-processor ? I'm going to look into the assembly
> language of the
> arm-processor, but maybe someone knows this immediately.
> For old processors like 8085 or Z80 I know how to do this, but
> arm-assembler is new to me.
> Thanks for any hints.
You might also look into the RBIT instruction which does this in one cpu
d.html and applied to the STM32 USART
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