OSCILLATOR CIRCUITS

KS57C2308/P2308/C2316/P2316

 

 

+PROGRAMMING TIP — Setting the CPU Clock

To set the CPU clock to 0.95 µs at 4.19 MHz:

BITS

EMB

SMB

15

LD

A,#3H

LD

PCON,A

INSTRUCTION CYCLE TIMES

The unit of time that equals one machine cycle varies depending on whether the main system clock (fx) or a subsystem clock (fxt) is used, and on how the oscillator clock signal is divided (by 4, 8, or 64). Table 6-2 shows corresponding cycle times in microseconds.

Table 6-2. Instruction Cycle Times for CPU Clock Rates

Oscillation

Selected

Resulting

Cycle Time (µ s)

Source

CPU Clock

Frequency

 

 

 

 

 

fx = 4.19 MHz

fx/64

65.5 kHz

15.3

 

 

 

 

 

fx/8

524.0 kHz

1.91

 

 

 

 

 

fx/4

1.05 MHz

0.95

 

 

 

 

fxt = 32.768 kHz

fxt/4

8.19 kHz

122.0

 

 

 

 

6-6

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Image 176
Samsung KS57C2308 manual + Programming TIP Setting the CPU Clock, Pcon,A, Instruction Cycle Times