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Chapter 12
Asynchronous Serial Interface A (UARTA)
User’s Manual U16702EE3V2UD00
12.5 Operation
12.5.1 Data
format
Full-duplex serial data is transmitted or received.
The transmit/receive data is in the format shown in Figure 12-9, consisting of a start bit, character bits,
a parity bit, and 1 or 2 stop bits.
The character bit length in one data frame, parity, stop bit length, and whether data is transferred with
the MSB or LSB first, are specified by the UAnCTL0 register.
The UAnTDL bit of the UAnOPT0 register is used to specify whether the signal output from the TXDAn
pin is inverted or not.
•
Start bit
… 1 bit
•
Character bit … 7 or 8 bits
•
Parity bit
… Even parity, odd parity, 0 parity, or no parity
•
Stop bit
… 1 or 2 bits
Figure 12-9:
Format of Transmit/Receive Data of UARTA (1/2)
(a) 8-bit data length, LSB first, even parity, 1 stop bit, transfer data: 55H
(b) 8-bit data length, MSB first, even parity, 1 stop bit, transfer data: 55H
(c) 8-bit data length, MSB first, even parity, 1 stop bit, transfer data: 55H, TXDAn inverted
1 data frame
Start
bit
D0
D1
D2
D3
D4
D5
D6
D7 Parity
bit
Stop
bit
1 data frame
Start
bit
D7
D6
D5
D4
D3
D2
D1
D0
Parity
bit
Stop
bit
D7
D6
D5
D4
D3
D2
D1
D0
1 data frame
Start
bit
Parity
bit
Stop
bit
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