W78E58B Winbond, W78E58B Datasheet - Page 6

• Manufacturer Part Number: W78E58B
• Description: 8 BIT MICROCONTROLLER
• Manufacturer: Winbond

Power Management
Idle Mode
Setting the IDL bit in the PCON register enters the idle mode. In the idle mode, the internal clock to the
processor is stopped. The peripherals and the interrupt logic continue to be clocked. The processor will
exit idle mode when either an interrupt or a reset occurs.
Power-down Mode
When the PD bit in the PCON register is set, the processor enters the power-down mode. In this mode
all of the clocks are stopped, including the oscillator. To exit from power-down mode is by a hardware
reset or external interrupts INT0 to INT1 when enabled and set to level triggered.
Reduce EMI Emission
The W78E58B allows user to diminish the gain of on-chip oscillator amplifier by using programmer to
clear the B7 bit of security register. Once B7 is set to 0, a half of gain will be decreased. Care must be
taken if user attempts to diminish the gain of oscillator amplifier, reducing a half of gain may affect the
external crystal operating improperly at high frequency. The value of C1 and C2 may need some
adjustment while running at lower gain.
Reset
The external RESET signal is sampled at S5P2. To take effect, it must be held high for at least two
machine cycles while the oscillator is running. An internal trigger circuit in the reset line is used to
deglitch the reset line when the W78E58B is used with an external RC network. The reset logic also
has a special glitch removal circuit that ignores glitches on the reset line. During reset, the ports are
initialized to FFH, the stack pointer to 07H, PCON (with the exception of bit 4) to 00H, and all of the
other SFR registers except SBUF to 00H. SBUF is not reset.
W78E58B Special Function Registers (SFRs) and Reset Values
F0
E8
E0
D8
D0
C8
C0
B8
B0
F8
00000000
00000000
00000000
00000000
00000000
00000000
00000000
xxxx1111
+T2CON
XICON
+PSW
+ACC
+P4
+P3
+IP
+B
00000000
00000000
P4CONA
RCAP2L
00000000
00000000
RCAP2H
P4CONB
- 6 -
00000000
00000000
00000000
SFRAL
P43AL
TL2
00000000
00000000
00000000
SFRAH
P43AH
TH2
00000000
00000000
CHPENR
SFRFD
W78E58B
00000000
CHPCON
0xx00000
SFRCN
EF
DF
CF
BF
FF
F7
E7
D7
C7
B7