Figure 9. Clock And Reset Circuit - STMicroelectronics SPC58XCADPT176S User Manual

External Oscillato r
J21
EVB-EXTAL 3
EVB-EXTAL
R5
1
DNP
STRIP 2mm
Y1
J23
40MHZ
3
R6 R7 0R
1
DNP
STRIP 2mm
Loop Controlled Pierce
VSS_OSC
Oscillator Circuit
GND
REMOVE XTAL jumper when driving EXTAL from
Oscillator Module or External Source (PLL Enabled)
Connect XTAL jumper to GND when driving EXTAL from
Oscilaltor Module or External Source (PLL Bypass
Mode)
Reset Circuit
VDD_HV_IO_MAIN
R9 10K R10 560R
SW1
Pushbutton
GND
RST-SW
RST-SW (pg6)
Figure 9. Clock and reset circuit
External Clock Inpu t
2 EXTAL
EXTAL (pg3)
(MCU Crystal Input)
Note - Internal
Pull-Up on Pin 1
2 XTAL
XTAL(pg3)
(MCU Crystal Output)
SMA style
Connector
USR RESET LED VDD_HV_IO_MAIN
D1 Yellow
R11
4K7
VCC J27
2 3 1 2 RST-MCU
GND STRIP 2mm
GND Reset-In
Disable
U3A
74LVC125AMTR
9
GND
GND
3.3V_SR
J22
C58 100nF
2 1
STRIP 2mm
Note - External 3.3V
regulator MUST be
U2
enabled when using
VDD
oscillator module
1 OE CLK 3
OUT
GND
8MHz
GND J24
OSC-MOD 1
EXTAL-SMA 3
STRIP 2mm
P1 1
R8 100R
GND
VDD_HV_IO_MAIN
R13
4K7
J25
5 6 1 2 ESR0
ESR0 (pg3,5)
U3B STRIP 2mm
74LVC125AMTR
MCU RESET LED
R12 560R
D4
Red
1 VCC
4
2
GND
U4
MC74HC1G08DTT1G
GND
J26
8 1 2 PORST
PORST (pg3,5)
U3C STRIP 2mm
74LVC125AMTR R14
4K7 VDD_HV_IO_MAIN
2
EVB-EXTAL
EVB-EXTAL