Cypress FM4 Series - Setup Procedure Example

CHAPTER 12: I/O Port
FM4 Peripheral Manual, Doc. No. 002-04856 Rev. *E 591
3. Setup Procedure Example
This section explains a procedure example of setting up the I/O port.
Setup of the I/O Port
By setting registers of the I/O port, select I/O direction and select GPIO/peripheral.
Figure 3-1 shows a setup procedure example.
Figure 3-1 Setup Procedure Example of the I/O Port
Start
Set peripherals
EPFR peripheral output enabled
Note: Output follows fixed priority
EPFR peripheral input enabled
Special pin selected
Yes
Yes
No
No
No
Set GPIO, PDOR output value setting
enabled
Yes
PFR=1?
Set peripheral output?
ADE/SPSR/DAE=1?
No special pin
DDR=0?
Set GPIO input
PDIR readable
Yes
No
The pin doubles as a
special pin?
Set GPIO output
No
Yes
Set EPFR Set peripheral pins