Freescale Semiconductor, Inc.
Table 2-5. Signal Summary
Signal Name
Address Bus
Mnemonic
A23–A0
Input/Output
Out
Active State
—
Three-State
Yes
Address Bus Port A7–A0/
Interrupt Acknowledge
A31–A24
Out/I/O/Out
—/—/Low
Yes
Data Bus
D15–D0
FC3–FC0
CS3–CS1
I/O
Out
—
—
Yes
Yes
No
Function Codes
Chip Select 3/Interrupt Request
Level/Port B4, B2, B1
Out/In/I/O
Low/Low/—
Chip Select 0/Autovector
Bus Request
CS0
BR
Out/In
In
Low/Low
Low
No
—
No
—
—
Bus Grant
BG
Out
In
Low
Bus Grant Acknowledge
Data and Size Acknowledge
BGACK
Low
DSACK1,
DSACK0
In
Low
Read-Modify-Write Cycle
Address Strobe
Data Strobe
RMC
AS
Out
Out
Low
Low
Yes
Yes
Yes
Yes
Yes
—
DS
Out
Low
Size
SIZ1, SIZ0
R/W
Out
—
Read/Write
Out
High/Low
Low/—
Interrupt Request Level/
Port B7, B6, B5, B3
IRQ7, IRQ6,
IRQ5, IRQ3
In/I/O
Reset
RESET
HALT
I/O
I/O
Low
Low
Low
—
No
No
Halt
Bus Error
BERR
In
—
System Clock
Crystal Oscillator
External Filter Capacitor
Clock Mode Select/Port B0
CLKOUT
EXTAL, XTAL
XFC
Out
No
In, Out
In
—
—
—
—
MODCK
IFETCH/DSI
In/I/O
Out/In
—/—
Low/—
—
Instruction Fetch/
No/—
Development Serial In
Instruction Pipe/
Development Serial Out
IPIPE/DSO
Out/Out
In/In
Low/—
Low/—
No/—
—/—
Breakpoint/
BKPT/DSCLK
Development Serial Clock
Freeze
FREEZE
Out
In
High
—
No
—
Receive Data
RxDA, RxDB
2- 14
MC68340 USER’S MANUAL
MOTOROLA
For More Information On This Product,
Go to: www.freescale.com
FREESCALE [ Freescale ]
