[En-Nut-Discussion] SPI-Clock Ethernut 3

[Harald Kipp]

Christoph Hillebrand wrote:

> I work with Ethernut 3 Board, which has an AT91400008 MCU. I use
> SPI-Bitbanging. 
> 
> Now it works nearly correct, but the clock signal is too low. I´ve got a
> clock with a frequency of 20kHz and I need a frequency from 125 kHz to
> 4,8MHz. How could I adjust this frequency.

Christoph,

with software it would be very difficult if not impossible to reach this 
speed. 4.8MHz would require to do one loop in 16 cycles.

The only chance I see is too implement another SPI in the CPLD. The 
standard Verilog file already contains the SPI for the MMC interface so 
it should be that difficult.

Harald