upd78f0124hgba1-8et-a Renesas Electronics Corporation., upd78f0124hgba1-8et-a Datasheet - Page 107

• Manufacturer Part Number: upd78f0124hgba1-8et-a
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

5.4.3 When subsystem clock is not used
connect the XT1 and XT2 pins as follows.
5.4.4 Internal oscillator
oscillation clock always oscillates after RESET release (240 kHz (TYP.)).
5.4.5 Prescaler
speed system clock is selected as the clock to be supplied to the CPU.
If it is not necessary to use the subsystem clock for low power consumption operations and watch operations,
XT1: Connect directly to EV
XT2: Leave open
Note When the subsystem clock is not used, the on-chip feedback resistor must be set after a reset is released
Remark The feedback resistor is required to control the bias point of the oscillation waveform so that the bias
Internal oscillator is incorporated in the 78K0/KD1+.
“Can be stopped by software” or “Cannot be stopped” can be selected using the option byte. The internal
The prescaler generates various clocks by dividing the high-speed system clock oscillator output when the high-
Caution When the internal oscillation clock is selected as the clock supplied to the CPU, the prescaler
so that it is not used (bit 6 (FRC) of processor clock control register (PCC) = 1).
point is in the middle of the power supply voltage.
generates various clocks by dividing the internal oscillator output (f
SS
Figure 5-11. Subsystem Clock Feedback Resistor
or V
SS
Feedback resistor
XT1
Note
CHAPTER 5 CLOCK GENERATOR
User’s Manual U16962EJ3V0UD
P-ch
FRC
XT2
X
= 240 kHz (TYP.)).
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