Clkcon – Samsung S3F80JB User Manual

Page 74

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S3F80JB

CONTROL REGISTERS

4-7

CLKCON

— System Clock Control Register

D4H Set1 Bank0

Bit

Identifier

.7 .6 .5 .4 .3 .2 .1 .0

Reset Value

0 0 0 0 0 0 0 0

Read/Write

R/W R/W R/W R/W R/W R/W R/W R/W

Addressing Mode

Register addressing mode only

.7 – .5

Not used for S3F80JB

.4 and .3

CPU Clock (System Clock) Selection Bits

(1)

0 0

f

OSC

/16

0 1

f

OSC

/8

1 0

f

OSC

/2

1 1

f

OSC

(non-divided)

.2 – .0

Subsystem Clock Selection Bits

(2)

1

0

1

Not used for S3F80JB.

Other value

Select main system clock (MCLK)

NOTES:
1. After a reset, the slowest clock (divided by 16) is selected as the system clock. To select faster clock speeds, load the

appropriate values to CLKCON.3 and CLKCON.4.

2. These selection bits CLKCON.0, .1, .2 are required only for systems that have a main clock and a subsystem clock. The

S3F80JB uses only the main oscillator clock circuit. For this reason, the setting '101B' is invalid.

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