M6759_1 Datasheet, PDF (10/33 Pages) List of Unclassifed Manufacturers – 8-bit MTP Micro-controller

Acer Laboratories Inc.
--Proprietary, Confidential, Preliminary--
M6759: 8 bit MTP Micro-controller
3.9 Interrupt Priorities
There are two stages of interrupt priority assignment,
interrupt level and natural priority. The interrupt level
(high or low) takes precedence over natural priority. All
interrupts can be assigned to be high or low priority. In
addition to an assigned priority level, each interrupt also
has a natural priority, as listed in Table 3-2. Simultaneous
interrupts with the same priority level (for example, both
high) are resolved according to their natural priority. For
example, if /INT0 and /INT1 are both programmed as high
priority, /INT0 takes precedence.
Once an interrupt is being serviced, only an interrupt of
higher priority level can interrupt the service routine of the
interrupt currently being serviced.
Mode
Idle
Idle
Power Down
Power Down
Program Memory ALE
/PSEN
Port0
Port1
Port2
Internal
1
1
Data
Data
Data
External
1
1
Float
Data
Address
Internal
0
0
Data
Data
Data
External
0
0
Float
Data
Data
Table 3-1. Status of the External pins During Idle and Power Down
Port3
Data
Data
Data
Data
Reset Timing
XTAL1
205 clocks
State3 State4 State5 State6 State1 State2 State3 State4 State5
RST
INTERNAL RESET SIGNAL
ALE
/PSEN
P0
XTAL1
RST
FF
ADDR
INST
29 clocks
STATE STATE STATE STATE STATE STATE STATE
ADDR
INST
STATE3 STATE4 STATE5
INTERNAL RESET SIGNAL
ALE
/PSEN
P0
ADDR
INST
ADDR
FF
FF
Ver. 1.01, Document Number : 6759DS02.doc
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