XR21V1412 View Datasheet(PDF) - Exar Corporation

Part Name

Description

Manufacturer

XR21V1412

2-CH FULL-SPEED USB UART

Exar Corporation 

XR21V1412

2-CH FULL-SPEED USB UART

REV. 1.0.0

3.3.5 CHARACTER_FORMAT Register Description (Read/Write)

This register controls the character format such as the word length (7, 8 or 9), parity (odd, even, forced ’0’, or

forced ’1’) and number of stop bits (1 or 2).

CHARACTER_FORMAT[3:0]: Data Bits.

TABLE 9: DATA BITS

DATA BITS

CHARACTER_FORMAT[3:0]

7

0111

8

1000

9

1001

All other values for CHARACTER_FORMAT[3:0] are reserved.

CHARACTER_FORMAT[6:4]: Parity Mode Select

These bits select the parity mode. If 9-bit data mode has been selected, then writing to these bits will not have

any effect. In other words, there will not be an additional parity bit.

TABLE 10: PARITY SELECTION

BIT-6

BIT-5

BIT-4

PARITY SELECTION

0

0

0

No parity

0

0

1

Odd parity

0

1

0

Even parity

0

1

1

Force parity to mark, “1”

1

0

0

Force parity to space, “0”

CHARACTER_FORMAT[7]: Stop Bit select

This register selects the number of stop bits to add to the transmitted character and how many stop bits to

check for in the received character.

TABLE 11: STOP BIT SELECTION

BIT-7

NUMBER OF STOP BITS

0

1 stop bit

1

2 stop bits

3.3.6 FLOW_CONTROL Register Description (Read/Write)

These registers select the flow control mode. These registers should only be written to when the UART is

disabled. Writing to the FLOW_CONTROL register when the UART is enabled will result in undefined

behavior.

18

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