Linux BSP v1.
Linux BSP v1.
Linux BSP v1.
Linux BSP v1.2
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29
Obviously, the value should be 0x0.
b.
To begin the experiment, set the value of GPIO 20-23 output enable
registers to be high state.
# devmem2 0xd81100b0 b 0xf0
# devmem2 0xd81100b0 b 0xf0
# devmem2 0xd81100b0 b 0xf0
# devmem2 0xd81100b0 b 0xf0
/* Write GPIO 20-23 Output Enable Registers*/
c.
Then set the value of GPIO 20-23 output data registers also to be high
state.
# devmem2 0xd81100f0 b 0xf0
# devmem2 0xd81100f0 b 0xf0
# devmem2 0xd81100f0 b 0xf0
# devmem2 0xd81100f0 b 0xf0
/* Write GPIO 20-23 Output Data Registers*/
Now GPIO 20-23 should output the high state, which changes the low state of
GPIO 24-27 to be high state.
d.
Examine the value of GPIO 24-27 input data register value.
# devmem2 0xd8110031 b
# devmem2 0xd8110031 b
# devmem2 0xd8110031 b
# devmem2 0xd8110031 b
/* Read GPIO 24-27 input Registers*/