AT89C51IC2 Atmel Corporation, AT89C51IC2 Datasheet - Page 14

• Manufacturer Part Number: AT89C51IC2
• Manufacturer: Atmel Corporation

Specifications of AT89C51IC2

• Flash (kbytes): 32 Kbytes
• Max. Operating Frequency: 60 MHz
• Cpu: 8051-12C
• Max I/o Pins: 34
• Spi: 1
• Twi (i2c): 1
• Uart: 1
• Sram (kbytes): 1.25
• Self Program Memory: API
• Operating Voltage (vcc): 2.7 to 5.5
• Timers: 4
• Isp: UART
• Watchdog: Yes

Oscillators
Overview
Registers
14
AT89C51IC2
Two oscillators are available for CPU:
•
•
Several operating modes are available and programmable by software:
•
•
In order to optimize the power consumption and the execution time needed for a specific
task, an internal prescaler feature has been implemented between the selected oscilla-
tor and the CPU.
Table 14. CKSEL Register
CKSEL - Clock Selection Register (85h)
Reset Value = 0000 000’HSB.OSC’b (see Hardware Security Byte (HSB) Table 84)
Not bit addressable
Number
OSCA used for high frequency: Up to 48 MHz @5V +/- 10%
OSCB used for low frequency: 32.768 kHz
to switch OSCA to OSCB and vice-versa
to stop OSCA or OSCB to reduce consumption
Bit
7
-
7
6
5
4
3
2
1
0
Mnemonic Description
CKS
Bit
6
-
-
-
-
-
-
-
-
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
CPU Oscillator Select Bit: (CKS)
Cleared, CPU and peripherals connected to OSCB
Set, CPU and peripherals connected to OSCA
Programmed by hardware after a Power-up regarding Hardware Security Byte
(HSB).HSB.OSC (Default setting, OSCA selected)
5
-
4
-
3
-
2
-
1
-
4301D–8051–02/08
CKS
0