Writing to a register

firewater

I

Post Edited (firewater) : 7/19/2008 6:10:37 PM GMT

Bruce Bates

firewater -

You need to read the entire BYTE into the Stamp, using SHIFTIN. Then you can modify just the top bit using the AND operator with a mask of $7F which will set the top bit off. Then re-write the BYTE using SHIFTOUT.

Regards,

Bruce Bates

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔

Franklin

You need to take what you got with the read, AND it with $7f and then send it back the first byte would be %10011010 ($1a with the MSB set to 1) the second byte would be the result of the previous read anded with $7f.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
- Stephen

Bruce Bates

firewater -

The following code is from your program:

set_LASER_CTRLO = LASER_CTRLO & MASK 'value from read and MSB set to 1)

If you are trying to set the high bit on, you want to do this:

set_LASER_CTRLO = LASER_CTRLO | $80 'value from read and MSB set to 1)

To set a bit OFF you use AND (&) with a mask that specifies everything BUT the bit(s) to be turned OFF. To set a bit ON you use OR (|) with a mask that specifies the bit(s) to be turned ON.

Regards,

Bruce Bates

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔