mpc82g516a Megawin Technology, mpc82g516a Datasheet - Page 114

• Manufacturer Part Number: mpc82g516a
• Description: 8-bit Microcontroller
• Manufacturer: Megawin Technology

22 System Clock
There are two clock sources for the system clock: external crystal oscillator and the built-in oscillator. The system
clock, Fosc, is obtained from one of these two clock sources through the clock divider, as shown in Figure 22-1.
The user can program the divider control bits SCKD2~SCKD0 (in PCON2 register) to get the desired system
clock.
The built-in oscillator is enabled by the hardware option ENROSC. Refer to
Figure 22-1. Block Diagram of System Clock
PCON2 (Address=C7H, Power Control Register 2, Reset Value=00x0,0000B)
SCKD2~SCKD0: System clock divider control bits.
SCKD2 SCKD1 SCKD0
22.1 Built-in Oscillator
The MPC82G516A has a built-in oscillator with the rough oscillating frequency of 6MHz. It can be used to replace
the external crystal oscillator in the application which doesn’t need an exact oscillating frequency. To enable the
built-in oscillator, the user should enable the hardware option ENROSC by a universal Writer/Programmer.
Typically, the oscillating frequency is about 6MHz at room temperature (25°C). And, the variation may be up to ±
30% over the temperature of –40°C to +85°C (+30% at –40°C, and –30% at +85°C).
application which does not require an exact oscillating frequency.
MEGAWIN
0
0
0
0
1
1
1
1
7
-
External
Crystal
Oscillator
0
0
1
1
0
0
1
1
6
-
0
1
0
1
0
1
0
1
XTAL1
XTAL2
5
-
Oscillating
Circuit
Built-in
Oscillator
Fosc (System Clock)
1: Disable
0: Enable
4
-
OSC_Freq
OSC_Freq /2
OSC_Freq /4
OSC_Freq /8
OSC_Freq /16
OSC_Freq /32
OSC_Freq /64
OSC_Freq /128
MPC82G516A Data Sheet
ENROSC
Hareware Option
1: Disabled (default)
0: Enabled
3
-
1
0
OSC_Freq
SCKD2
2
SCKD1
System Clock
1
SCKD2~SCKD0
Divider
SCKD0
Section 25: MCU’s Hardware
0
Fosc
System Clock
So, it is only for the
Option.
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