AT89LP51ID2 Atmel Corporation, AT89LP51ID2 Datasheet - Page 60

• Manufacturer Part Number: AT89LP51ID2
• Manufacturer: Atmel Corporation

Specifications of AT89LP51ID2

• Flash (kbytes): 64 Kbytes
• Max. Operating Frequency: 20 MHz
• Cpu: 8051-1C
• Max I/o Pins: 42
• Spi: 1
• Twi (i2c): 1
• Uart: 1
• Adc Channels: 7
• Adc Resolution (bits): 10
• Adc Speed (ksps): 153.8
• Sram (kbytes): 2.25
• Eeprom (bytes): 4096
• Self Program Memory: API
• Operating Voltage (vcc): 2.4 to 5.5
• Timers: 4
• Isp: SPI/OCD/UART
• Watchdog: Yes

8.4
60
Low Power Configuration
AT89LP51RD2/ED2/ID2 Preliminary
Several of the nonvolatile User Configuration Fuses can enable modes where less power will be
consumed during normal operation as listed in
once by an external programmer to match the desired operating environment.
Table 8-2.
Table 8-3.
Fuse Name
Clock Source A
X2 Mode
Low Power Mode
• For crystal frequencies of 12 MHz or less, OSCA should be placed in Low Power Crystal
• X1 Mode is supported for compatibility with existing applications. X2 Mode should be used to
• The Low Power Mode settings change the slope and intercept of the active current versus
FFH (1)
00H (0)
Fuse 1
(0EH)
Oscillator mode
achieve the same CPU and peripheral speed at half the crystal frequency
frequency relationship. See
—
FFH (1)
FFH (0)
00H (0)
Fuse 0
(0DH)
User Configuration Fuses Affecting Power Consumption
Low Power Mode Fuses
Extra Low
Power
Normal
Mode
Low Power
Table 8-3
Description
Lowest power mode. Use only if the oscillator frequency can
never be above 1 MHz.
Low power mode will reduce consumption for CPU frequencies
under 10 MHz and slightly increase consumption for CPU
frequencies over 10 MHz compared to Normal Mode. This
mode is best for oscillator frequencies below 10 MHz or for
frequencies 10–20 MHz where the prescaler may be used to
scale the CPU frequency below 10 MHz.
Normal mode has higher consumption than Low Power mode
for CPU frequencies under 10 MHz but slightly less
consumption for CPU frequencies over 10 MHz. This mode is
best for oscillator frequencies over 20 MHz or for frequencies
10–20 MHz where the prescaler is not used to scale the CPU
frequency.
Description
The Low Power Crystal Oscillator (setting 2) will use half the
power of the High Speed Crystal Oscillator (setting 3) for the
same frequency ( ≤ 12 MHz)
X2 mode can keep the same CPU speed while cutting the
crystal frequency in half.
Low Power Mode can reduce the power consumption for
system frequencies under 20 MHz. Extra Low Power Mode
can further reduce the power if the system frequency is less
than 1 MHz.
below.
Table
8-2. These fuses must generally be set
3714A–MICRO–7/11