AT83C5122_08 ATMEL [ATMEL Corporation], AT83C5122_08 Datasheet - Page 49

• Manufacturer Part Number: AT83C5122_08
• Description: C51 Microcontroller with USB and Smart Card Reader Interfaces
• Manufacturer: ATMEL [ATMEL Corporation]

4202F–SCR–07/2008
Table 26. Clock Configuration Register 0 - CKCON0 (S:8Fh)
Reset Value = X0X0 X000b
Bit Number Bit Mnemonic Description
7
-
7
6
5
4
3
2
1
0
WDX2
6
WDX2
T1X2
T0X2
SIX2
X2
-
-
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
Watchdog clock
This control bit is validated when the CPU clock X2 is set; when X2 is low,
this bit has no effect.
Cleared to bypass the 1/2 prescaler.
Set to select the 1/2 output for this peripheral.
Reserved
The value read from this bit is indeterminate. Do not set this bit.
Enhanced UART clock (Mode 0 and 2)
This control bit is validated when the CPU clock X2 is set; when X2 is low,
this bit has no effect.
Cleared to bypass the 1/2 prescaler.
Set to select the 1/2 output for this peripheral.
Reserved
The value read from this bit is indeterminate. Do not set this bit.
Timer 1 clock
This control bit is validated when the CPU clock X2 is set; when X2 is low,
this bit has no effect.
Cleared to bypass the 1/2 prescaler.
Set to select the 1/2 output for this peripheral.
Timer 0 clock
This control bit is validated when the CPU clock X2 is set; when X2 is low,
this bit has no effect.
Cleared to bypass the 1/2 prescaler.
Set to select the 1/2 output for this peripheral.
System clock Control bit
Cleared to select the PRT output for CPU and all the peripherals .
Set to bypass the PRT prescaler and to enable the individual peripherals ‘X2’
bits.
5
-
AT83R5122, AT8xC5122/23
SIX2
4
3
-
T1X2
2
T0X2
1
X2
0
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