Hi,
We are working with custom AM1808 board,need to program a peripheral device over a single wire interface using GPIO.
We are drive GPIO from logic high to Tri-state and then back to logic low.
for data pattern 1 and 0.
NOTE:
GPIO of concern is GP8[11],using linux gpio driver.
At kernel level in da850.c pinmuxs have been configured for GPIO mode
for GP8[11].
At user space:
./gpiotoggle 139
echo $1 > /sys/class/gpio/export
while [ 1 ]
do
echo 1 > /sys/class/gpio/gpio$1/value
echo "out" > /sys/class/gpio/gpio$1/direction
sleep 0.001
echo "in" > /sys/class/gpio/gpio$1/direction
sleep 0.00001
echo 1 > /sys/class/gpio/gpio$1/value
echo "out" > /sys/class/gpio/gpio$1/direction
sleep 0.001
echo "in" > /sys/class/gpio/gpio$1/direction
sleep 0.00001
done
Observations:
1>On driving GPIO to LOW : 0.0V is observed
2>On driving GPIO to Tristate from LOW:1.8 V is observed
3>On driving GPIO to HIGH from Tristate: 1.8 is observed instead of 3.3 V
4>On driving GPIO to LOW from tristate :0V is observed
Is any body facing similar issue ? how to fix this issue .
Thanks in advance for any suggestions,
-
Gururaj
