Hi, Ryan, On Mar 18, 2013, at 2:21 PM, Ryan Monroe wrote:
> root@roach:/proc/618/hw/ioreg# echo 0 > ../ioreg_mode > root@roach:/proc/618/hw/ioreg# echo -e \x00\x00\x00\x00 > acc_always_valid > -bash: echo: write error: Invalid argument You need to either double up the backslashes or put the \x00\x00\x00\x00 in quotes. Also adding -n is probably needed to suppress the newline. I think the invalid argument error is due to writing too many bytes (when ioreg_mode is 0). > root@roach:/proc/618/hw/ioreg# echo 1 > ../ioreg_mode > root@roach:/proc/618/hw/ioreg# echo -e \x00\x00\x00\x00 > acc_always_valid > root@roach:/proc/618/hw/ioreg# cat acc_always_valid > x00xroot@roach:/proc/618/hw/ioreg# Here the shell ate the backslashes so you as before you tried to write "x00x00x00x00" to the register. I guess ioreg_mode of 1 is more tolerant of trailing data, so only the first 4 bytes, "x00x" got written to the register (as confirmed by the output of the cat command). Hope this helps, Dave
