ah yes echo -ne "\x00\x00\x00\x00" | hd 00000000 00 00 00 00
On Mon, Mar 18, 2013 at 11:49 PM, David MacMahon <[email protected]>wrote: > 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 > > -- *Adam Barta* c: +27 72 105 8611 e: [email protected] w: www.ska.ac.za
