Preliminary W78LE516
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 W78LE516 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 ana 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 W78LE516 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.
W78LE516 Special Function Registers (SFRs) and Reset Values
F8
F0
E8
E0
D8
D0
C8
C0
B8
+ACC
00000000
+P4
xxxx1111
+PSW
00000000
+T2CON
00000000
XICON
00000000
+IP
00000000
RCAP2L
00000000
P4CONA
00000000
RCAP2H
00000000
P4CONB
00000000
TL2
00000000
SFRAL
00000000
TH2
00000000
SFRAH
00000000
SFRFD
00000000
SFRCN
00000000
CHPCON
0xx00000
+B
00000000
CHPENR
00000000
FF
F7
EF
E7
DF
D7
CF
C7
BF
-6-
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