C 8 0 5 1 F 3 3 6 / 7 / 8 / 9
12
Rev. 0.3
5.11. Target Board Pin Assignment Summary
Some GPIO pins of the C8051F338 MCU can have an alternate fixed function. For example, pin 22 on the 'F338
MCU is designated P0.4, and can be used as a GPIO pin. Also, if the UART0 peripheral on the MCU is enabled
using the crossbar registers, the TX signal is routed to this pin. This is shown in the "Alternate Fixed Function"
column. The "Target Board Function" column shows that this pin is used as TX on the 'F338 Target Board. The
"Relevant Headers" column shows that this signal is routed to pin 7 of the J1 header and pin 5 of the J3 header.
More details can be found in the C8051F336/7/8/9 data sheet. Some of the GPIO pins of the C8051F338 have
been used for various functions on the target board. Table 6 summarizes the MCU pin assignments on the target
board, and also shows the various headers associated with each signal.
Table 6. C8051F338 Target Board Pin Assignments and Headers
MCU Pin Name
Pin#
Primary
Function
Alternate Fixed
Function
Target Board
Function
Relevant Headers
P0.0
2
P0.0
VREF
VREF
J1[3], TB1[6]*, J5[1]
P0.1
1
P0.1
IDAC
IDAC
J1[4], J1[2]*, TB1[2], J6[1]
P0.2
24
P0.2
XTAL1
XTAL1
J1[5]*, J9[2]
P0.3
23
P0.3
XTAL2
XTAL2
J1[6]*, J10[2]
P0.4
22
P0.4
TX_MCU
TX_MCU
J1[7], J3[5]
P0.5
21
P0.5
RX_MCU
RX_MCU
J1[8], J3[7]
P0.6
20
P0.6
CNVSTR
CNVSTR
J1[9], TB1[1]
P0.7
19
P0.7
SW2 (switch)
J1[10], J3[3]
P1.0
18
P1.0
CP0A
J1[11], J11[1]
P1.1
17
P1.1
RTS
J1[12], J3[9]
P1.2
16
P1.2
CTS
J1[13], J3[11]
P1.3
15
P1.3
LED
J1[14], J3[1]
P1.4
14
P1.4
AIN
J1[15], TB1[4]
P1.5
13
P1.5
AIN
J1[16], TB1[3]
P1.6
12
P1.6
POT
J1[17], J8[1]
P1.7
11
P1.7
GPIO
J1[18]
P2.0
10
P2.0
CP0+
J1[19], J11[3]
P2.1
9
P2.1
CP0-
J1[20], J11[5]
P2.2
8
P2.2
GPIO
J1[21]
P2.3
7
P2.3
T0
J1[22], J11[7]
P2.4/C2D
6
P2.4
C2D
P2.4/C2D
J1[23]*, J4[6]*, J4[4]
/RST/C2CK
5
/RST
C2CK
/RST/C2CK
J1[24]*, J4[5]*, J4[7]
VDD
4
VDD
VDD
J2[2]
GND
3
GND
GND
J1[25], J1[26], TB1[5]
*Note:
Headers denoted by this symbol are not directly connected to the MCU pin; the connection might be via one or more
headers and/or pin-sharing resistor(s). See board schematic for details.
