RH850/U2A 292pin
4. Clock Supply
R20UT4970ED0101 Rev.1.01
Page 26 of 67
July 08, 2022
4. Clock Supply
The device's operation clock can be generated by
•
the on-chip oscillator main oscillator circuit in combination with an off-chip resonator, connected to the X1, X2
terminals
•
an off-chip oscillator, the clock is fed into the X1 terminal
4.1
Main Oscillator
For operating the on-chip main oscillator the piggyback board provides a socket (X1) for a
resonator.
Optionally a resonator (X3) can be soldered on the board, refer to the figure above.
Several resonators for various main oscillator frequencies (16 MHz, 20 MHz, 24 MHz,
40 MHz) are included in the board package.
The 40MHz resonator is by default mounted to X1.
For package content please refer to
CAUTION
Only one oscillator, either X1 or X3, can be used at any one time for the main oscillator.
20 MHz provide additional
24 MHz provide additional
16 MHz provide additional
crystal
CAUTION!
18pF
0
DNF
/DNB
DNF/DNB
0
1K0
DNF/DNB
22p
SG8018CE-20.000000MHz
100n
22p
P3V3
3.3V
DNF
/DNB
8pF
16MHz
40.000 MHz + socket
DNF/DNB
0
DNF/DNB
DNF/DNB
R1
C16
OSC1
R4
R2
R3
X1
C97
C98
X3
2D3
2D2
X2
X2_C
X1_C
X1
3
2
1
4
E20
F20
X2
X1
IN
OUT
OE
VCC
GND
CLK
Figure 4.1 Clock supply
