mpc823rg Freescale Semiconductor, Inc, mpc823rg Datasheet - Page 929

• Manufacturer Part Number: mpc823rg
• Description: Mpc823 Powerquicc Integrated Communications Processor For Portable Systems
• Manufacturer: Freescale Semiconductor, Inc

16.14.3 The Port A Registers
Port A has four 16-bit, memory-mapped, read/write control registers.
16.14.3.1 PORT A OPEN-DRAIN REGISTER. The port A open-drain register (PAODR)
indicates when the port pins are configured in a normal or wired-OR configuration. Three of
the PAODR bits can be open-drain to correspond to those pins that have serial channel
output capability. The other bits are always zero. PAODR is cleared by system reset.
Bits 0–8, 10–11, 13 and 15—Reserved
These bits are reserved and must be set to 0.
OD9–OD15—Open-Drain Pins 9-15
16.14.3.2 PORT A DATA REGISTER. A read of the port A data (PADAT) register returns
the data at the pin, regardless of whether the pin is defined as an input or output. This allows
output conflicts to be found on the pin by comparing the written data with the data on the pin.
A write to the PADIR is latched and if the bit is configured as an output, the value latched for
that bit is driven onto its respective pin. PADAT is not initialized and is undefined at reset.
Bits 0–3—Reserved
These bits are reserved and must be set to 0.
D4–D15—Data Pins 4-15
The value written into these bits may be read on the Port A pins.
PAODR
PADAT
RESET
RESET
FIELD
ADDR
FIELD
ADDR
R/W
R/W
BIT
BIT
0 = The I/O pin is actively driven as an output.
1 = The I/O pin is an open-drain driver. As an output, the pin is actively driven low.
Otherwise, it is three-stated.
0
0
RESERVED
1
1
R/W
0
2
2
Freescale Semiconductor, Inc.
For More Information On This Product,
3
3
RESERVED
R/W
D4
MPC823 REFERENCE MANUAL
4
0
4
0
Go to: www.freescale.com
R/W
D5
5
5
0
(IMMR & 0xFFFF0000) + 0x956
(IMMR & 0xFFFF0000) + 0x954
R/W
D6
6
6
0
R/W
D7
7
7
0
R/W
R/W
D8
8
8
0
OD9
R/W
R/W
D9
9
9
0
0
Communication Processor Module
D10
R/W
RESERVED
10
10
0
R/W
0
R/W
D11
11
11
0
OD12
R/W
D12
R/W
12
12
0
0
R/W
RES
D13
R/W
13
13
0
0
OD14
R/W
R/W
D14
14
14
0
0
16-477
R/W
RES
R/W
D15
15
15
0
0