MC68332
OVERVIEW
USER’S MANUAL
3-9
3.5 Intermodule Bus
The intermodule bus (IMB) is a standardized bus developed to facilitate both design
and operation of modular microcontrollers. It contains circuitry to support exception
processing, address space partitioning, multiple interrupt levels, and vectored inter-
rupts. The standardized modules in the MCU communicate with one another and with
external components through the IMB. The IMB in the MCU uses 24 address and 16
data lines.
3.6 System Memory Map
through
dresses of internal registers.
maps that use different external decoding schemes.
Function Codes
FC[2:0]
Identify processor state and current address space
Freeze
FREEZE
Indicates that the CPU has entered background mode
Halt
HALT
Suspend external bus activity
Instruction Pipeline
IPIPE, IFETCH Indicate instruction pipeline activity
Interrupt Request Level
IRQ[7:1]
Provides an interrupt priority level to the CPU
Master In Slave Out
MISO
Serial input to QSPI in master mode;
serial output from QSPI in slave mode
Clock Mode Select
MODCLK
Selects the source and type of system clock
Master Out Slave In
MOSI
Serial output from QSPI in master mode;
serial input to QSPI in slave mode
Port C
PC[6:0]
SIM digital output port signals
Auxiliary Timer Clock Input
PCLK
External clock dedicated to the GPT
Peripheral Chip Select
PCS[3:0]
QSPI peripheral chip selects
Port E
PE[7:0]
SIM digital I/O port signals
Port F
PF[7:0]
SIM digital I/O port signals
Port QS
PQS[7:0]
QSM digital I/O port signals
Quotient Out
QUOT
Provides the quotient bit of the polynomial divider
Reset
RESET
System reset
Read-Modify-Write Cycle
RMC
Indicates an indivisible read-modify-write instruction
Read/Write
R/W
Indicates the direction of data transfer on the bus
SCI Receive Data
RXD
Serial input to the SCI
QSPI Serial Clock
SCK
Clock output from QSPI in master mode;
clock input to QSPI in slave mode
Size
SIZ[1:0]
Indicates the number of bytes to be transferred during a bus cycle
Slave Select
SS
Causes serial transmission when QSPI is in slave mode;
causes mode fault in master mode
TCR2 Clock
T2CLK
External clock source for TCR2 counter
TPU Channel Pins
TPUCH[15:0] Bidirectional pins associated with TPU channels
Three-State Control
TSC
Places all output drivers in a high-impedance state
SCI Transmit Data
TXD
Serial output from the SCI
External Filter Capacitor
XFC
Connection for external phase-locked loop filter capacitor
Table 3-5 MCU Signal Function (Continued)
Signal Name
Mnemonic
Function
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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