Content originally posted in LPCWare by kisiel on Sat Aug 17 15:20:09 MST 2013
I expected good result at 48Mhz also, but GPIO gives me random values on 5V signal,
in assy is:
ldr r1,=GPIO
ldr r0,[r1]
ldr r2,[r1]
cmp r0,r2
...
I have tried so far:
pull up pull down hysteresis on/off, I checked signals with logic analyser (e.g. USBee-AX-Pro) and source signals are "flat" in time then GPIO is read.
I will change cortex M0 to M3 maybe this will help.