UPD78F0500AMC-CAB-AX Renesas Electronics America, UPD78F0500AMC-CAB-AX Datasheet - Page 248

• Manufacturer Part Number: UPD78F0500AMC-CAB-AX
• Description: MCU 8BIT 30SSOP
• Manufacturer: Renesas Electronics America
• Series: 78K0/Kx2r

Specifications of UPD78F0500AMC-CAB-AX

• Core Processor: 78K/0
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: 3-Wire SIO, I²C, LIN, UART/USART
• Peripherals: LVD, POR, PWM, WDT
• Number Of I /o: 23
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 4x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

78K0/Kx2
6.6 Controlling Clock
6.6.1 Example of controlling high-speed system clock
R01UH0008EJ0401 Rev.4.01
Jul 15, 2010
Remark While the microcontroller is operating, a clock that is not used as the CPU clock can be stopped via software
The following two types of high-speed system clocks are available.
• X1 clock:
• External main system clock: External clock is input to the EXCLK pin.
When the high-speed system clock is not used, the X1/P121 and X2/EXCLK/P122 pins can be used as I/O port pins.
Caution The X1/P121 and X2/EXCLK/P122 pins are in the I/O port mode after a reset release.
The following describes examples of setting procedures for the following cases.
(1) When oscillating X1 clock
(2) When using external main system clock
(3) When using high-speed system clock as CPU clock and peripheral hardware clock
(4) When stopping high-speed system clock
(1) Example of setting procedure when oscillating the X1 clock
<1> Setting frequency (OSCCTL register)
<2> Setting P121/X1 and P122/X2/EXCLK pins and selecting X1 clock or external clock (OSCCTL register)
<3> Controlling oscillation of X1 clock (MOC register)
Using AMPH, set the gain of the on-chip oscillator according to the frequency to be used.
Note Set AMPH before setting the peripheral functions after a reset release. The value of AMPH can be
Remark f
When EXCLK is cleared to 0 and OSCSEL is set to 1, the mode is switched from port mode to X1 oscillation
mode.
If MSTOP is cleared to 0, the X1 oscillator starts oscillating.
settings. The internal high-speed oscillation clock and high-speed system clock can be stopped by executing
the STOP instruction (see (4) in 6.6.1 Example of controlling high-speed system clock, (3) in 6.6.2
Example of controlling internal high-speed oscillation clock, and (4) in 6.6.3 Example of controlling
subsystem clock).
AMPH
EXCLK
0
1
0
changed only once after a reset release. When AMPH is set to 1, the clock supply to the CPU is
stopped for 4.06 to 16.12
Note
XH
1 MHz ≤ f
10 MHz < f
: High-speed system clock oscillation frequency
OSCSEL
1
Crystal/ceramic resonator is connected across the X1 and X2 pins.
XH
XH
X1 oscillation mode
≤ 10 MHz
Speed System Clock Pin
Operation Mode of High-
≤ 20 MHz
μ
s.
Operating Frequency Control
Crystal/ceramic resonator connection
P121/X1 Pin
CHAPTER 6 CLOCK GENERATOR
P122/X2/EXCLK Pin
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