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17.3.2.3 Port Control Registers
As shown in
Figure
port pins of Port 3. Additionally to the PISEL register programming, the required ASC
port lines must be programmed by software for the desired ASC input/output
functionality. Two selections must be executed:
•
Input/output function selection
(controlled by the port input/output control registers IOCR)
•
Pad driver characteristics selection for the outputs
(controlled by the port pad driver mode register PDR)
Input/Output Function Selection
The port input/output control registers contain the 4-bit wide bit fields that select the
digital output and input driver characteristics such as pull-up/down devices, port direction
(input/output), open-drain, and alternate output selections individually for each pin. The
I/O lines for the ASC modules are controlled by the port input/output control registers
P3_IOCR0, P3_IOCR8 and P3_IOCR12.
Table 17-8
shows how bits and bit fields must be programmed for the required I/O
functionality of the ASC I/O lines. This table also shows the values of the peripheral input
select registers.
Table 17-8
ASC0/ASC1 I/O Control Selection and Setup
Module Port Lines
ASC0
P3.0/RXD0A
P3.12/RXD0B ASC0_PISEL.RIS = 1 P3_IOCR12.PC12 = 0XXX
P3.1/TXD0
P3.13/TXD0
ASC1
P3.9/RXD1A
P3.14/RXD1B ASC1_PISEL.RIS = 1 P3_IOCR12.PC14 = 0XXX
P3.8/TXD1
P3.15/TXD1
1) Applicable in Synchronous Mode only.
User's Manual
ASC, V1.3 2007-11
Asynchronous/Synchronous Serial Interface (ASC)
17-12, the I/O lines of the ASC modules are connected to Class A2
PISEL Register
ASC0_PISEL.RIS = 0 P3_IOCR0.PC0 = 0XXX
–
–
–
–
ASC1_PISEL.RIS = 0 P3_IOCR8.PC9 = 0XXX
–
–
–
–
Input/Output Control
Register Bits
P3_IOCR0.PC0 = 1X01
P3_IOCR12.PC12 = 1X01
P3_IOCR0.PC1 = 1X01
P3_IOCR12.PC13 = 1X10
P3_IOCR8.PC9 = 1X01
P3_IOCR12.PC14 = 1X01
P3_IOCR8.PC8 = 1X10
P3_IOCR12.PC15 = 1X10
17-39
TC1728
I/O
Input
B
1)
Output
B
Input
B
1)
Output
B
Output
B
Output
B
Input
B
1)
Output
B
Input
B
1)
Output
B
Output
B
Output
B
V1.0, 2011-12
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