AN2866 Freescale Semiconductor / Motorola, AN2866 Datasheet - Page 17

• Manufacturer Part Number: AN2866
• Description: Migrating from the MC68332 to the ColdFire MCF523x
• Manufacturer: Freescale Semiconductor / Motorola

2.4.1.9
Like the MC68332, unused bus interface and peripheral pins on the MCF523x can be used as discrete
general-purpose inputs and outputs. These are managed by a dedicated GPIO module that logically groups
all pins into ports located within a contiguous block of memory-mapped control registers.
All of the pins associated with the external bus interface may be used for several different functions. Their
primary function is to provide an external memory interface to access off-chip resources. When not used
for this, all of the pins may be used as general-purpose digital I/O pins. In some cases, the pin function is
set by the operating mode, and the alternate pin functions are not supported.
The primary difference between the MC68332 and the MCF523x is the number of GPIOs supported. The
MC68332 has up to 32 GPIOs, but the MCF523x supports up to 81 GPIO pins.
2.4.1.10 PLL and Clocks
Similar to the MC68332, the clock module on the MCF523x allows it to be configured for one of
several clocking methods. However, the clock module on the MCF523x has much more
functionality. Clocking modes include internal frequency modulated phase-locked loop (PLL)
clocking with either an external clock reference or an external crystal reference supported by an
internal crystal amplifier. The PLL can also be disabled and an external oscillator can be used to
clock the device
Table 6
Freescale Semiconductor
Programmable interrupt triggering
contrasts the features of the MC68332 and the MCF523x PLL.
Number of external interrupts
General Purpose I/O Module
Feature
directly.
Migrating from the MC68332 to the ColdFire
Table 5. External Interrupt Pin and EPORT Differences
Interrupt Pins
—
7
EPORT
Up to 7
√
®
MCF523x, Rev. 1.0
device’s except for the QFP version of
the MCF5232 which has 3 IRQ signals
There are 7 IRQ signals on all 523x
Level, rising or falling edge, or both
available (IRQ7, IRQ4, & IRQ1)
rising and falling edges
Comments
Device Differences
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