56F8355_07 Datasheet, PDF (21/164 Pages) Freescale Semiconductor, Inc – 16-bit Digital Signal Controllers

Signal Pins
Table 2-2 Signal and Package Information for the 128-Pin LQFP (Continued)
Signal Name Pin No. Type
State
During
Reset
Signal Description
GPIOB4
31
Schmitt
Input,
Port B GPIO — This GPIO pin can be individually programmed as
Input/
pull-up an input or output pin.
Output
enabled
(A20)
Output
Address Bus — A20 specifies one of the address lines for
external program or data memory accesses. Depending upon the
state of the DRV bit in the EMI bus control register (BCR), A20
and EMI control signals are tri-stated when the external bus is
inactive.
(prescaler_
clock)
Output
Clock Output — can be used to monitor the prescaler_clock on
GPIOB4.
After reset, the default state is GPIO.
This pin can also be used to view the prescaler_clock. In these
cases, the GPIOB_PER can be used to disable the GPIO. The
CLKOSR register in the SIM can then be used to choose between
address and clock functions; see Part 6.5.7 for details.
D7
(GPIOF0)
D8
(GPIOF1)
D9
(GPIOF2)
D10
(GPIOF3)
To deactivate the internal pull-up resistor, clear clear bit 4 in the
GPIOB_PUR register.
22
Input/
In reset, Data Bus — D7 - D10 specify part of the data for external
Output
output is program or data memory accesses. Depending upon the state of
disabled, the DRV bit in the EMI bus control register (BCR), D7 - D10 are
pull-up is tri-stated when the external bus is inactive
enabled
Input/
Port F GPIO — These four GPIO pins can be individually
Output
23
programmed as input or output pins.
After reset, these pins default to data bus functionality and should
be programmed as GPIO.
24
To deactivate the internal pull-up resistor, clear the appropriate
26
GPIO bit in the GPIOF_PUR register.
Example: GPIOF0, clear bit 0 in the GPIOF_PUR register.
Note: Primary function is not available in this package
configuration; GPIO function must be used instead.
56F8355 Technical Data, Rev. 12
Freescale Semiconductor
21
Preliminary