mpc823rg Freescale Semiconductor, Inc, mpc823rg Datasheet - Page 933

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

16.14.5 Port B Pin Functionality
All port B pins can be open-drain and are independently configured as general-purpose
I/O pins if the corresponding bit in the PBPAR is cleared. They are configured as dedicated
on-chip peripheral pins if the corresponding PBPAR bit is set. When configured as a
general-purpose I/O pin, the signal direction of that pin is determined by the corresponding
control bit in the PBDIR. The port B pin is configured as an input if the corresponding PBDIR
bit is cleared and as an output if the corresponding PBDIR bit is set. All PBPAR bits and
PBDIR bits are cleared by total system reset, which configures all port B pins as
general-purpose input pins. Refer to Table 16-42 for a description of all port B pin options.
If a port B pin is used as a general-purpose I/O pin, it can be accessed with the PBDAT
where data is stored in an output latch. If a port B pin is configured as an output, the output
latch data is gated onto the port pin. When PBDAT is read, the port pin itself is read. If a port
B pin is configured as an input, data written to PBDAT is still stored in the output latch, but
is prevented from reaching the port pin. When PBDAT is read, the state of the port pin is
read. Many of the port B pins have more than one function, including on-chip peripheral
functions for SPI, I
in that their on-chip peripheral functions (BRGO2 and BRGO1) are also used in port A. This
allows an alternate way to output the BRGO pins if other functions are used. PB18 and PB16
are also unusual in that their on-chip peripheral functions (RTS2 and L1RQA) are used in
port C, which is an alternate location to output these pins if using other functions on port C.
SIGNAL
PB31
PB30
PB29
PB28
PB27
PB26
PB25
PB24
PB23
PB22
PB19
PB18
PB17
PB16
PBPAR = 0
PORT B31
PORT B30
PORT B29
PORT B28
PORT B27
PORT B26
PORT B25
PORT B24
PORT B23
PORT B22
PORT B19
PORT B18
PORT B17
PORT B16
2
C, SMC1, SMC2, SCC3, TDM, and LCD. PB27 and PB26 are unusual
Freescale Semiconductor, Inc.
For More Information On This Product,
Table 16-42. Port B Pin Assignment
MPC823 REFERENCE MANUAL
PBDIR = 0
SMRXD1
SMSYN1
SMSYN2
SMTXD1
SPISEL
BRGO3
BRGO1
BRGO2
L1ST1
L1ST2
L1ST3
L1ST4
TXD3
RXD3
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PBPAR = 1
PIN FUNCTION
PBDIR = 1
SPIMOSI
SPIMISO
SDACK1
SDACK2
SPICLK
I2CSDA
I2CSCL
LCD_C
L1RQA
LCD_A
LCD_B
RTS2
Communication Processor Module
SPIMOSI=V
SPIMISO = SPIMOSI
INPUT TO ON-CHIP
SMSYN1 = GND
SMSYN2 = GND
PERIPHERALS
SPICLK = GND
I2CSCL = GND
I2CSDA= V
SPISEL=V
(RXD3)
DD
—
—
—
—
—
—
;
TXD3 = PB24
DD
DD
16-481