AT89C51ID2-SMSIM ATMEL [ATMEL Corporation], AT89C51ID2-SMSIM Datasheet - Page 57

• Manufacturer Part Number: AT89C51ID2-SMSIM
• Description: 8-bit Flash Microcontroller
• Manufacturer: ATMEL [ATMEL Corporation]

Internal Baud Rate Generator
(BRG)
Figure 25. Internal Baud Rate
4289A–8051–09/03
BRR
F
PER
Table 36. Baud Rate Selection Table UART
When the internal Baud Rate Generator is used, the Baud Rates are determined by the
BRG overflow depending on the BRL reload value, the value of SPD bit (Speed Mode)
in BDRCON register and the value of the SMOD1 bit in PCON register.
•
Baud_Rate =
BRL = 256 -
(T2CON)
The baud rate for UART is token by formula:
TCLK
X
X
X
0
1
0
1
0
1
/6
6
6
(1-SPD)
(1-SPD)
2
2
SPD
(T2CON)
SMOD1
SMOD1
0
1
RCLK
32 (256 -BRL)
32 Baud_Rate
0
0
1
1
0
1
X
X
X
auto reload counter
F
F
PER
PER
BRG
BRL
(BDRCON)
TBCK
0
0
0
0
1
1
0
0
1
overflow
(BDRCON)
RBCK
/2
0
0
0
0
0
0
1
1
1
SMOD1
0
1
Clock Source
UART Tx
INT_BRG
INT_BRG
INT_BRG
Timer 1
Timer 2
Timer 1
Timer 2
Timer 1
Timer 2
AT89C51ID2
INT_BRG
Clock Source
UART Rx
INT_BRG
INT_BRG
INT_BRG
Timer 1
Timer 1
Timer 2
Timer 2
Timer 1
Timer 2
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