Figure 9.
Clock and reset circuit
External Oscillator
Reset Circuit
External Clock Inpu t
Note - External 3.3V
regulator MUST be
enabled when using
oscillator module
SMA style
Connector
Note - Internal
Pull-Up on Pin 1
Loop Controlled Pierce
Oscillator Circuit
(MCU Crystal Input)
(MCU Crystal Output)
Connect XTAL jumper to GND when driving EXTAL from
Oscilaltor Module or External Source (PLL Bypass
Mode)
REMOVE XTAL jumper when driving EXTAL from
Oscillator Module or External Source (PLL Enabled)
MCU RESET LED
USR RESET LED
Reset-In
Disable
GND
GND
3.3V_SR
VSS_OSC
GND
GND
GND
VDD_HV_IO_MAIN
VDD_HV_IO_MAIN
GND
GND
GND
VDD_HV_IO_MAIN
VDD_HV_IO_MAIN
EXTAL (pg3)
XTAL(pg3)
EVB-EXTAL
RST-SW (pg6)
ESR0 (pg3,5)
PORST (pg3,5)
EVB-EXTAL
C58
100nF
R12
560R
R10
560R
R13
4K7
CLK
OUT
VDD
GND
OE
8MHz
U2
4
2
3
1
GND
VCC
U4
MC74HC1G08DTT1G
1
2
4
5
3
J27
STRIP 2mm
1
2
R6
DNP
J26
STRIP 2mm
1
2
U3B
74LVC125AMTR
5
6
4
VCC
GND
U3A
74LVC125AMTR
2
3
14
1
7
J22
STRIP 2mm
1
2
R5
DNP
R8 100R
R14
4K7
J23
STRIP 2mm
1
2
3
J24
STRIP 2mm
1
2
3
R7 0R
R11
4K7
R9 10K
SW1
Pushbutton
P1
1
2
4
3
5
D1 Yellow
J21
STRIP 2mm
1
2
3
D4
Red
J25
STRIP 2mm
1
2
U3C
74LVC125AMTR
9
8
10
Y1
40MHZ
1
2
OSC-MOD
EVB-EXTAL
EXTAL-SMA
EXTAL
XTAL
EVB-EXTAL
ESR0
PORST
RST-MCU
RST-SW
UM2763
-
Rev 1
page
18
/24
UM2763
Schematics