AT89LP51ED2 Atmel Corporation, AT89LP51ED2 Datasheet - Page 114

• Manufacturer Part Number: AT89LP51ED2
• Manufacturer: Atmel Corporation

Specifications of AT89LP51ED2

• 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

17.2.3
114
AT89LP51RD2/ED2/ID2 Preliminary
Internal Baud Rate Generator (BRG)
Table 17-4.
The AT89LP51RD2/ED2/ID2 includes an Internal Baud Rate Generator (BRG) for UART modes
1 and 3 that can free up Timer 1 or Timer 2 for other uses. The BRG is an 8-bit counter with
reload as shown in
is controlled by the BDRCON register (See
SPD bit determines the clock source: either the system clock divided-by-6 or the system clock
with no division. The BRG is not affected by the Timer Prescaler; however, it is affected by the
SMOD1 bit in PCON. The following equation shows the baud rate calculation using the BRG:
The output of the Internal Baud Rate Generator can be independently selected for the transmit
and receive clocks using the TBCK and RBCK bits in BDRCON. These bits have priority over
the TCLK and TCLK bits in T2CON as shown in
baud rates generated by the BRG.
Baud Rate
Max: 750K
19.2K
19.2K
137.5
137.5
9.6K
4.8K
2.4K
1.2K
9.6K
4.8K
2.4K
1.2K
110
110
110
Commonly Used Baud Rates Generated by Timer 2
f
OSC
Figure
11.059
11.059
11.059
11.059
11.059
11.986
11.059
11.059
11.059
11.059
11.059
11.986
12
12
12
(MHz)
6
Baud Rate
17-1. On overflow, the BRG is loaded with the value of BRL. The BRG
X2
=
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
2
------------------- -
SMOD1
32
CP/RL2
Table
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
×
------------------------------- -
256
17-7). The BRG operates when BRR = 1. The
Table
f
–
SYS
C/T2
(
BRL
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
17-2.
)
×
------------------------
6
TCLK or RCLK
Table 17-5
(
Timer 2
1 SPD
–
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
)
lists some common
3714A–MICRO–7/11
Reload Value
FFDCH
FFDCH
FEE0H
FDC0H
EAB8H
FFEEH
FEE0H
FFFFH
FFB8H
F2AFH
E55EH
FFB8H
F55CH
F2AFH
FF70H
FF70H