Typewriter User Manual

MOTOROLA MC68340 USER’S MANUAL 2- 3
Table 2-1. Signal Index (Continued)
Signal Name Mnemonic Function
Input/
Output
Clock Mode Select/
Port B0
MODCK Selects the source of the internal system clock upon reset
or becomes a parallel I/O port
In/I/O
Instruction Fetch/
Development Serial In
IFETCH/DSI Indicates when the CPU32 is performing an instruction
word prefetch and when the instruction pipeline has been
flushed or provides background debug mode serial in
Out/In
Instruction Pipe/
Development Serial Out
IPIPE/DSO Used to track movement of words through the instruction
pipeline or provides background debug mode serial out
Out/Out
Breakpoint/Development
Serial Clock
BKPT/DSCLK Signals a hardware breakpoint to the CPU32 or provides
background debug mode serial clock
In/—
Freeze FREEZE Indicates that the CPU32 has entered background debug
mode
Out
Transmit Data TxDA, TxDB Transmitter serial data output from the serial module Out
Clear-to-Send CTSA, CTSB Serial module clear-to-send inputs In
Request-to-Send/
OP1, OP0
RTSB, RTSA Channel request-to-send outputs or discrete outputs Out/Out
Serial Crystal Oscillator X1, X2 Connections for an external crystal to the serial module
internal oscillator circuit
Serial Clock SCLK External serial module clock input In
Transmitter Ready/OP6 T≈RDYA Indicates transmit buffer has a character or becomes a
parallel output
Out/Out
Receiver Ready/
FIFO Full/OP4
R≈RDYA Indicates receive buffer has a character, the receiver
FIFO buffer is full or becomes a parallel output
Out/Out/Out
DMA Request DRE
Q2, DREQ1
Input that starts a DMA process In
DMA Acknowledge DACK2,
DACK1
Output that signals an access during DMA Out
DMA Done DONE2,
DONE1
Bi-directional signal that indicates the last transfer I/O
Timer Gate TGATE2,
TGATE1
Counter enable input to timer In
Timer Input TIN2, TIN1 Time reference input to timer In
Timer Output TOUT2,
TOUT1
Output waveform from timer Out
Test Clock TCK Provides a clock for IEEE 1149.1 test logic In
Test Mode Select TMS Controls test mode operations In
Test Data In TDI Shifts in instructions and test data In
Test Data Out TDO Shifts out instructions and test data Out
Synchronizer Power V
CCSYN
Quiet power supply to VCO; also used to control
synthesizer mode after reset.
—
System Power Supply
and Ground
V
CC
, GND Power supply and ground to the MC68340 —
Frees
cale Semiconductor,
I
Freescale Semiconductor, Inc.
For More Information On This Product,
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