SN8F2280 Series
USB 2.0 Full-Speed 8-Bit Micro-Controller
3
RESET
3.1 OVERVIEW
The system would be reset in three conditions as following.
z
z
z
z
Power on reset
Watchdog reset
Brown out reset
External reset (only supports external reset pin enable situation)
When any reset condition occurs, all system registers keep initial status, program stops and program counter is cleared.
After reset status released, the system boots up and program starts to execute from ORG 0. The NT0, NPD flags
indicate system reset status. The system can depend on NT0, NPD status and go to different paths by program.
086H
PFLAG
Read/Write
After reset
Bit 7
NT0
R/W
-
Bit 6
NPD
R/W
-
Bit 5
Bit 4
Bit 3
Bit 2
C
R/W
0
Bit 1
DC
R/W
0
Bit 0
Z
R/W
0
-
-
-
-
-
-
-
-
-
Bit [7:6] NT0, NPD: Reset status flag.
NT0
0
0
1
1
NPD
Condition
Watchdog reset
Reserved
Power on reset and LVD reset. Power voltage is lower than LVD detecting level.
External reset External reset pin detect low level status.
Description
Watchdog timer overflow.
-
0
1
0
1
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Version 1.1
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