Slow spi communications

Projects Networking, Protocols, and Devices
1

Hi I am using spi to communicate with a sensor. The problem is that I am using an optocoupler, but the turn on time and turn off time of this particular optocoupler is too slow. Even dividing the clock by 128, the spi is too fast for the optocoupler.
Is there anyway to slow the SPI clock even more?

Thanks in advance
/Joc

2

Is this communication be directional ? Please show the schematic which includes your Arduino board, the opto-coupler and the sensor (with part numbers).

3

I found the solution here:
Decrease SPI clock speed - #8 by Smajdalf
One way is to use
#include <avr/power.h>
and in the setup do
clock_prescale_set(clock_div_2);

However, I used "clock_div_8". Now it's working.

4

it is SPI. There is one line MISO and one MOSI, plus the clock and slave select. I have an opto on each line.