MC97F2664
April 11, 2014 Ver. 1.4
173
The process for detecting stop bit is like clock and data recovery process. That is, if 2 or more samples of 3
center values have high level, correct stop bit is detected, else a frame error (FEn) flag is set. After deciding
whether the first stop bit is valid or not, the Receiver goes to idle state and monitors the RXD line to check a valid
high to low transition is detected (start bit detection).
Figure 11.39 Stop Bit Sampling and Next Start Bit Sampling (where n = 2,3, and 4)
11.10.8 Register Map
Table 11-15 UART Register Map (where n = 2,3, and 4)
Name
Address
Dir
Default Description
UARTnBD
103CH/1044H/104CH (XSFR)
R/W
FFH
UARTn Baud Rate Generation Register
UARTnDR
103DH/1045H/104DH (XSFR)
R/W
00H
UARTn Data Register
UARTnCR1 1038H/1040H/1048H (XSFR)
R/W
00H
UARTn Control Register 1
UARTnCR2 1039H/1041H/1049H (XSFR)
R/W
00H
UARTn Control Register 2
UARTnCR3 103AH/1042H/104AH (XSFR)
R/W
00H
UARTn Control Register 3
UARTnST
103BH/1043H/104BH (XSFR)
R/W
80H
UARTn Status Register
11.10.9 UART Register Description
UART2/3/4 module consists of UART2/3/4 baud rate generation register (UARTnBD), UART2/3/4 data register
(UARTnDR), UART2/3/4 control register 1 (UARTnCR1), UART2/3/4 control register 2 (UARTnCR2) ,UART2/3/4
control register 3 (UARTnCR3), and UART2/3/4 status register (UARTnST).
11.10.10 Register Description for UART2/3/4
UARTnBD (UARTn Baud Rate Generation Register) : 103CH/1044H/104CH (XSFR), Where n = 2, 3, and 4
7
6
5
4
3
2
1
0
UARTnBD7
UARTnBD6
UARTnBD5
UARTnBD4
UARTnBD3
UARTnBD2
UARTnBD1
UARTnBD0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Initial value : FFH
UARTnBD [7:0]
The value in this register is used to generate internal baud rate. To
prevent malfunction, do not write
‘0’.
RXD
1
2
3
4
5
6
7
8
9
10
11
12
13
STOP 1
1
2
3
4
5
6
7
Sample
(U2Xn = 0)
Sample
(U2Xn = 1)
(A)
(B)
(C)
Содержание MC97F2664
Страница 20: ...MC97F2664 20 April 11 2014 Ver 1 4 4 Package Diagram Figure 4 1 64 Pin LQFP 1010 Package...
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