mc68331cpv20b1 Freescale Semiconductor, Inc, mc68331cpv20b1 Datasheet - Page 99

• Manufacturer Part Number: mc68331cpv20b1
• Description: Mc68331 32 Bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

4.9 Parallel Input/Output Ports
4.9.1 Pin Assignment Registers
4.9.2 Data Direction Registers
4.9.3 Data Registers
4.10 Factory Test
MC68331
USER’S MANUAL
Fifteen SIM pins can be configured for general-purpose discrete input and output. Al-
though these pins are organized into two ports, port E and port F, function assignment
is by individual pin. Pin assignment registers, data direction registers, and data regis-
ters are used to implement discrete I/O.
Bits in the port E and port F pin assignment registers (PEPAR and PFPAR) control the
functions of the pins in each port. Any bit set to one defines the corresponding pin as
a bus control signal. Any bit cleared to zero defines the corresponding pin as an I/O
pin.
Bits in the port E and port F data direction registers (DDRE and DDRF) control the di-
rection of the pin drivers when the pins are configured as I/O. Any bit in a register set
to one configures the corresponding pin as an output. Any bit in a register cleared to
zero configures the corresponding pin as an input. These registers can be read or writ-
ten at any time. Writes have no effect.
A write to the port E and port F data registers (PORTE and PORTF) is stored in an
internal data latch, and if any pin in the corresponding port is configured as an output,
the value stored for that bit is driven out on the pin. A read of a data register returns
the value at the pin only if the pin is configured as a discrete input. Otherwise, the value
read is the value stored in the register. Both data registers can be accessed in two lo-
cations. Registers can be read or written at any time.
The test submodule supports scan-based testing of the various MCU modules. It is in-
tegrated into the SIM to support production test. Test submodule registers are intend-
ed for Freescale use only. Register names and addresses are provided in APPENDIX
D REGISTER SUMMARY to show the user that these addresses are occupied. The
QUOT pin is also used for factory test.
Table 4-24 CSBOOT Base and Option Register Reset Values
Freescale Semiconductor, Inc.
Async/Sync Mode
Upper/Lower Byte
For More Information On This Product,
Address Space
Base Address
Read/Write
Autovector
Block Size
DSACK
AS/DS
Fields
SYSTEM INTEGRATION MODULE
IPL
Go to: www.freescale.com
Interrupt Vector Externally
Supervisor/User Space
Asynchronous Mode
13 Wait States
Reset Values
Read/Write
Both Bytes
Any Level
$000000
1 Mbyte
AS
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