89C5121-SK1 Atmel, 89C5121-SK1 Datasheet - Page 24

• Manufacturer Part Number: 89C5121-SK1
• Description: KIT SMART CARD FOR AT89C5121
• Manufacturer: Atmel
• Type: Smart Cardr

Specifications of 89C5121-SK1

• Contents: Board
• For Use With/related Products: AT89C5121
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: T89C5121-SK1; T89C5121-SK1

Clock Prescaler
Clock Control Registers
Clock Prescaler Register
24
A/T8xC5121
Before supplying the CPU and the peripherals, the main clock is divided by a factor 2 to
30 to reduce the CPU power consumption. This factor is controlled with the CKRL
register.
Table 7. Examples of Factors
This register is used to reload the clock prescaler of the CPU and peripheral clock.
Table 8. CKRL Register
CKRL - Clock Reload Register (97h)
Reset Value = XXXX 111Xb
XTAL (MHz)
Number
7 - 4
3 - 1
Bit
7
-
0
16
16
16
16
16
16
Mnemonic
X2 CPU CKCON0
CKRL
6
-
Bit
0 (reset mode)
1 (X2 mode)
-
-
1
0
0
1
Description
Reserved
The value read from this bit is indeterminate. Do not set this bit.
Clock Reload Register
Prescaler value
XXXX 000Xb: CKRL=7 and Division factor equals 14
XXXX 110Xb: CKRL=6 and factor equals 2
XXXX 111Xb: CKRL=7 and division factor equals 1
Reserved
The value read from this bit is indeterminate. Do not set this bit.
5
-
CKRL Value
4
-
07h
07h
07h
07h
06h
06h
CKRL
3
Prescaler Factor
CKRL
1
1
1
1
2
2
2
CKRL
F
1
CLK_CPU,
4164G–SCR–07/06
(MHz)
16
16
F
8
8
4
8
CLK_Periph
0
-