W77LE532_07 Datasheet, PDF (44/88 Pages) Winbond – 8-BIT MICROCONTROLLER

W77LE532/W77L532A
11. RESET STATE
Most of the SFRs and registers on the device will go to the same condition in the reset state. The
Program Counter is forced to 0000h and is held there as long as the reset condition is applied.
However, the reset state does not affect the on-chip RAM. The data in the RAM will be preserved
during the reset. However, the stack pointer is reset to 07h, and therefore the stack contents will be
lost. The RAM contents will be lost if the V_DD falls below approximately 2V, as this is the minimum
voltage level required for the RAM to operate normally. Therefore after a first time power on reset the
RAM contents will be indeterminate. During a power fail condition, if the power falls below 2V, the
RAM contents are lost.
After a reset most SFRs are cleared. Interrupts and Timers are disabled. The Watchdog timer is
disabled if the reset source was a POR. The port SFRs have FFh written into them which puts the port
pins in a high state. Port 0 floats as it does not have on-chip pull-ups.
Table 6. SFR Reset Value
SFR NAME
P0
SP
DPL
DPH
DPL1
DPH1
DPS
PCON
TCON
TMOD
TL0
TL1
TH0
TH1
CKCON
P1
P4CONA
P40AL
P41AL
P42AL
P43Al
CHPCON
ROMCON
SFRAH
SFRCN
RESET VALUE
11111111b
00000111b
00000000b
00000000b
00000000b
00000000b
00000000b
00xx0000b
00000000b
00000000b
00000000b
00000000b
00000000b
00000000b
00000001b
11111111b
00000000b
00000000b
00000000b
00000000b
00000000b
00000000b
00000111b
00000000b
00111111b
SFR NAME
IE
SADDR
P3
IP
SADEN
T2CON
T2MOD
RCAP2L
RCAP2H
TL2
TH2
TA
PSW
WDCON
ACC
EIE
P4CONB
P40AH
P41AH
P42AH
P43AH
P4CSIN
SFRAL
SFRFD
RESET VALUE
00000000b
00000000b
11111111b
x0000000b
00000000b
00000000b
00000x00b
00000000b
00000000b
00000000b
00000000b
11111111b
00000000b
0x0x0xx0b
00000000b
xxx00000b
00000000b
00000000b
00000000b
00000000b
00000000b
00000000b
00000000b
00000000b
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