External Crystal Oscillator And External Clock Circuit; External Crystal Input Circuit; External Clock Input Circuit (P1.6 Cannot Be Used As General I/O); Clock Stop / Power Saving Mode And System Power Management - STC micro STC8A8K64D4 Series Reference Manual

STC8A8K64D4 Series Manual

6.4 External crystal oscillator and external clock circuit

6.4.1 External crystal input circuit

6.4.2 External clock input circuit (P1.6 cannot be used as general I/O)

6.5 Clock stop / Power Saving Mode and System Power Management

Symbol Description
PCON Power control register

6.5.1 Power control register (PCON)

Symbol Address
PCON 87H
LVDF: Low voltage detection flag. When the system detects a low-voltage event, it is set by the hardware automatically and
an interrupt request to the CPU ocuurs. It should be cleared by user software.
POF: Power-On reset flag. It is set by the hardware automatically when power-off-on action occurs.
PD: Clock stop mode / Power-Down mode / Power stop mode control bit
0: No operation.
P1.6/XTALO
4~45MHz
P1.7/XTALI
Address
B7
87H SMOD
B7 B6
SMOD SMOD0
MCU
Bit Address and Symbol
B6 B5 B4
SMOD0 LVDF POF
B5 B4
LVDF POF
-
B3 B2 B1
GF1 GF0 PD
B3 B2 B1
GF1 GF0 PD
Reset
value
B0
IDL 0011,0000
B0
IDL
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