AT89C51RE2 Atmel Corporation, AT89C51RE2 Datasheet - Page 17

• Manufacturer Part Number: AT89C51RE2
• Manufacturer: Atmel Corporation

Specifications of AT89C51RE2

• Flash (kbytes): 128 Kbytes
• Max. Operating Frequency: 60 MHz
• Cpu: 8051-12C
• Max I/o Pins: 34
• Spi: 1
• Uart: 2
• Sram (kbytes): 8.25
• Self Program Memory: API
• Operating Voltage (vcc): 2.7 to 5.5
• Timers: 4
• Isp: UART/OCD
• Watchdog: Yes

7663E–8051–10/08
Table 16. CKCON1 Register
CKCON1 - Clock Control Register (AFh)
Reset Value = XXXX XX00b
Not bit addressable
Number
Bit
7
-
7
6
5
4
3
2
1
0
Mnemonic
SIX2_1
SPIX2
Bit
6
-
-
-
-
-
-
-
Description
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Enhanced UART1 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 select 6 clock periods per peripheral clock cycle. Set to select 12 clock
periods per peripheral clock cycle.
SPI (This control bit is validated when the CPU clock X2 is set; when X2 is low, this bit
has no effect).
Clear to select 6 clock periods per peripheral clock cycle.
Set to select 12 clock periods per peripheral clock cycle.
5
-
4
-
3
-
2
-
AT89C51RE2
SIX2_1
1
SPIX2
0
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