AT89LP51ED2-20AAU Atmel, AT89LP51ED2-20AAU Datasheet - Page 209

• Manufacturer Part Number: AT89LP51ED2-20AAU
• Description: 8-bit Microcontrollers - MCU 64KB 20MHz 2.4V-5.5V
• Manufacturer: Atmel

Specifications of AT89LP51ED2-20AAU

• Rohs: yes
• Core: 8051
• Processor Series: AT89x
• Data Bus Width: 8 bit
• Maximum Clock Frequency: 20 MHz
• Program Memory Size: 64 KB
• Data Ram Size: 256 B
• On-chip Adc: Yes
• Operating Supply Voltage: 2.4 V to 5.5 V
• Operating Temperature Range: - 40 C to + 85 C
• Package / Case: LQFP-44
• Mounting Style: SMD/SMT
• Data Rom Size: 4 KB
• Interface Type: 2-Wire, SPI, UART
• Number Of Programmable I/os: 36
• Number Of Timers: 3
• Program Memory Type: Flash
• Factory Pack Quantity: 160

24.5.5.3
3714A–MICRO–7/11
Autobaud Performance
The bootloader feature allows a wide range of baud rates in the user application. It is also adapt-
able to a wide range of oscillator frequencies. This is accomplished by measuring the bit-time of
a single bit in a received character. This information is then used to program the baud rate in
terms of timer counts based on the oscillator frequency. The bootloader feature requires that an
initial character (an uppercase U) be sent to the AT89LP51RD2/ED2/ID2 to establish the baud
rate.
For AT89LP51ID2 the bootloader always uses OSCA. If the device boots on OSCB, the boot-
loader will enable and switch to OSCA. In this case both the OSCA and OSCB sources must be
operational, i.e. a crystal or external clock source must be connected to the oscillator inputs
unless the oscillator source was previously configured as the internal RC oscillator.
Table 24-18. Autobaud Performance
Frequency
(MHz)
Baudrate (kHz)
2400
4800
9600
19200
38400
57600
115200
Frequency
(MHz)
Baudrate (kHz)
2400
4800
9600
19200
38400
57600
115200
Table 24-18
shows the autobaud capability.
1.8432
OK
OK
OK
OK
OK
OK
OK
OK
8
-
-
-
-
-
-
AT89LP51RD2/ED2/ID2 Preliminary
OK
OK
OK
OK
OK
10
2
-
-
-
-
-
-
-
-
-
11.0592
2.4576
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
-
-
OK
OK
OK
OK
OK
OK
OK
OK
OK
12
3
-
-
-
-
3.6864
14.746
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
-
OK
OK
OK
OK
OK
OK
OK
OK
OK
16
4
-
-
-
-
-
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
20
5
-
-
-
-
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
24
6
-
-
-
7.3728
26.6
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
-
209