JP21 is the GPIO port. The following table lists the pinout.
Table 3:
GPIO (JP21) Pinout
JP21 pin #
function
1
VCC
2
pin 51, PA0
3
pin 50, PA1
4
pin 49, PA2
5
pin 48, PA3
6
pin 47, PA4
7
pin 46, PA5
8
pin 45, PA6
9
pin 44, PA7
10
pin 6, PE4, INT4, OC3B
11
pin 7, PE5, INT5, OC3C
12
pin 8, PE6, INT6, T3
13
pin 9, PE7, INT7, IC3
This connector can be used for any application that only requires
TTL/CMOS level signals. Note that PE4 to PE7 can also serve as
special function pins.
