Cypress FM4 Series - Page 589

CHAPTER 12: I/O Port
FM4 Peripheral Manual, Doc. No. 002-04856 Rev. *E 589
Fixed Priority of EPFR Outputs
Only one output pin function among two or more outputs is allocated to one I/O port.
By setting the EPFR register, if more than one output is set, fixed priority is applied and output pins are
selected. Figure 2-4 shows output pins and fixed priority.
Figure 2-4 Output Pins and Fixed Priority
Fixed priority
function
Peripheral A output pin _0/
peripheral B output pin _1/
peripheral C output pin _0
Peripheral
macro C
Peripheral
macro B
Peripheral
macro A
Table 2-4 describes the fixed priority of EPFR.
Table 2-4 Fixed Priority of EPFR
Priority
Peripheral Function
Applied Pin
Higher
Special input
JTAG input, NMI input
↓
JTAG, trace
Output pin, I/O pin
↓
Ethernet-MAC
I/O pin
↓
High-Speed SPI controller
Output pin, I/O pin
↓
HyperBus Interface
Output pin, I/O pin
↓
HDMI-CEC
I/O pin
↓
USB (HCONX)
Output pin
↓
I2S
I/O pin
↓
CAN
Output pin
↓
MFS-I2S
Output pin, Input pin
↓
Multi-function serial
Output pin, I/O pin
↓
Base timer output
I/O pin
↓
Multi-function timer
Output pin
↓
External bus/SDRAM IF
Output pin, I/O pin
↓
SD card IF
Output pin, I/O pin
↓
Smart Card Interface
Output pin, I/O pin
↓
High speed CR oscillation output
Output pin
↓
RTC clock Output
Output pin
↓
SUBCLK Output
Output pin
Lower
GDC Panel Output
Output pin
Note:
− The fixed priority is only applicable when output is set for more than one function. In case of input,
there is no fixed priority.
However, Special input has a higher priority than any other output setting. When Special input is
set, the output setting allocated to the same port is invalid.
− Due to output setting on the lower part of the priority, the EPFR register always includes no output
setting.
− If you are going to use a pin as an external input pin of peripheral functions, disable all shared
output settings. If every output of a pin is not selected by the EPFR register, the pin works as an
external input pin.