Typewriter User Manual

MOTOROLA MC68340 USER’S MANUAL 3- 39
asserted, the A31–A0, FCx, SIZx, and R/W signals are again driven to their previous
states. The MC68340 does not service interrupt requests while it is halted.
CLKOUT
S0 S2 S4
R/W
AS
DS
HALT
S0 S2 S4
BR
BG
BGACK
S0
READ
HALT
(ARBITRATION PERMITTED
WHILE THE PROCESSOR IS
HALTED)
READ
DSACKx
A31–A0
FC3–FC0
D15–D10
Figure 3-21. HALT Timing
3.5.4 Double Bus Fault
A double bus fault results when a bus error or an address error occurs during the
exception processing sequence for any of the following:
• A previous bus error
• A previous address error
• A reset
For example, the MC68340 attempts to stack several words containing information about
the state of the machine while processing a bus error exception. If a bus error exception
Frees
cale Semiconductor,
I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
nc...