w79e532 Winbond Electronics Corp America, w79e532 Datasheet - Page 34

• Manufacturer Part Number: w79e532
• Description: 8-bit Microcontroller
• Manufacturer: Winbond Electronics Corp America

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
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
ROMCON
CHPCON
P4CONA
STATUS
CKCON
SFRAH
P40AL
P41AL
P42AL
PCON
TMOD
TCON
P43Al
PMR
DPH
DPL
TH0
TH1
TL0
TL1
SP
PC
P0
P1
RESET VALUE
11111111b
00000111b
00000000b
00000000b
000x0000b
00000000b
00000000b
00000000b
00000000b
00000000b
00000000b
00000000b
00000001b
11111111b
00000000b
00000000b
00000000b
00000000b
00000000b
00000000b
00000111b
00000000b
010xx0x0b
00xx0000b
DD
falls below approximately 2V, as this is the minimum
- 34 -
SFR NAME
RCAP2H
P4CONB
RCAP2L
WDCON
P4CSIN
SADDR
T2MOD
SADEN
T2CON
SFRFD
SFRAL
P40AH
P41AH
P42AH
P43AH
PSW
ACC
TH2
TL2
EIE
TA
P3
IE
IP
W79E532/W79L532
RESET VALUE
00000000b
00000000b
11111111b
x0000000b
00000000b
00000000b
00000x00b
00000000b
00000000b
00000000b
00000000b
11111111b
00000000b
00000000b
xxx
00000000b
00000000b
00000000b
00000000b
00000000b
00000000b
00000000b
00000000b
0x0x0xx0b
00000b