W78E516B
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 above 24 MHz. The value of R and C1, 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 W78E516B 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.
W78E516B Special Function Registers (SFRs) and Reset Values
F8
F0
E8
E0
D8
D0
C8
C0
B8
B0
A8
A0
98
90
88
80
FF
F7
EF
E7
DF
D7
CF
C7
BF
B7
AF
A7
9F
97
+B
CHPENR
00000000
00000000
+ACC
00000000
+P4
xxxx1111
+PSW
00000000
+T2CON
00000000
XICON
00000000
+IP
RCAP2L
RCAP2H
00000000
TL2
TH2
00000000
00000000
00000000
SFRAL
SFRAH
SFRFD
SFRCN
00000000
CHPCON
0xx00000
00000000
00000000
00000000
00000000
+P3
00000000
+IE
00000000
+P2
11111111
+SCON
00000000
+P1
SBUF
xxxxxxxx
11111111
+TCON
00000000
+P0
TMOD
00000000
SP
TL0
TL1
TH0
TH1
8F
87
00000000
DPL
00000000
DPH
00000000
00000000
PCON
11111111
00000111
00000000
00000000
00110000
Notes:
1.The SFRs marked with a plus sign(+) are both byte- and bit-addressable.
2. The text of SFR with bold type characters are extension function registers.
- 6 -
WINBOND [ WINBOND ]
