Double Bus Fault; Halt Timing - Motorola MC68340 User Manual

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
A31–A0
FC3–FC0
R/W
AS
DS
DSACKx
D15–D10
HALT
BR
BG
BGACK

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
MOTOROLA
Freescale Semiconductor, Inc.
S0 S2 S4
READ
(ARBITRATION PERMITTED
WHILE THE PROCESSOR IS
Figure 3-21. HALT Timing
MC68340 USER'S MANUAL
For More Information On This Product,
Go to: www.freescale.com
S0 S2
HALT READ
HALTED)
S4 S0
3- 39