AT89C51ID2-SLSIM Atmel, AT89C51ID2-SLSIM Datasheet - Page 56

• Manufacturer Part Number: AT89C51ID2-SLSIM
• Description: C51ID2 64KF TWI 32KHZ PLCC44 3-5.5V IND.
• Manufacturer: Atmel

Internal Baud Rate Generator
(BRG)
Figure 24. Internal Baud Rate
4289C–8051–11/05
BRR
F
PER
Table 37. 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
⋅ 32 ⋅ Baud_Rate
⋅ 32 ⋅ (256 -BRL)
RCLK
X
X
X
0
0
1
1
0
1
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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