MMC2107 - Freescale Semiconductor

Freescale Semiconductor, Inc.
Ports Module
Functional Description
11.5 Functional Description
The initial pin function is determined during reset configuration. The pin
assignment registers (PCDPAR and PEPAR) allow the user to select
between digital I/O or another pin function after reset.
In single-chip mode, all pins are configured as digital I/O by default.
Every digital I/O pin is individually configurable as an input or an output
via a data direction register (DDRx).
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Every port has an output data register (PORTx) and a pin data register
(PORTxP/SETx) to monitor and control the state of its pins. Data written
to PORTx is stored and then driven to the corresponding PORTx pins
configured as outputs.
Reading PORTx returns the current state of the register regardless of
the state of the corresponding pins.
Reading PORTxP returns the current state of the corresponding pins,
regardless of whether the pins are input or output.
Every port has a set register (PORTxP/SETx) and a clear register
(CLRx) for setting or clearing individual bits in PORTx.
In master mode and emulation mode, ports A and B function as the
upper external data bus, D[31:16]. When the PCDPA bit is set, ports C
and D function as the lower external data bus, D[15:0]. Ports E–I are
configured to support external memory and emulation functions.
In master mode, the function of EB[3:2] is determined by the PCDPA bit.
The function of CS[3:0] is determined by the individual chip select enable
(CSENx) bits.
MMC2107 – Rev. 2.0
Technical Data
MOTOROLA Ports Module 257
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