Pi 2 Design CM4AES Hardware Reference Manual – P0.1
PAGE 12
GPIO DIR
AF
PUP
PDN
CM4AES
Usage
Description/Notes
21
OUT
I2S
SDOUT
I2S Serial Data to WM8804
22
OUT
PUP
PHLD
Power Hold to Power Circuit
23
IN
PUP
*ROT_SW Rotary Center Switch, Routed to P17
24
IN
PUP
*PSW
Power On Switch from Power Circuit
25
IN
PUP
ROT_CK
Rotary Clock Switch, Routed to P17
26
IN
PUP
ROT_DT
Rotary Data Switch, Routed to P17
27
I/O
GPIO27
Routed to P1 Expansion Connector
Table 5 – CM4 Port and GPIO Pin Assignments
5.3.1
CM4 GPIO NOTES
3. DIR is from the point of view of the CM4.
4. Alternate Function (AF) column indicates that the use of this pin requires
the pin to be assigned to the named function as defined by the CM4
specifications.
5. PUP/PDN indicates if the GPIO should have its associated Pullup (PUP)
or Pulldown (PDN) resistor enabled.
6. An asterisk ‘*’ at the beginning of the name indicates a low true signal.
