Digi NS9750 User Manual

Page 636

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S e r i a l p o r t c o n t r o l a n d s t a t u s r e g i s t e r s

6 1 2

N S 9 7 5 0 H a r d w a r e R e f e r e n c e

D28

R/W

EPS

0

Even parity select

0

Odd parity

1

Even parity

Determines whether the serial channel uses odd or even
parity when calculating the parity bit in UART mode.

When the STICKP field is set, EPS defines the static state
for the parity bit.

D27

R/W

PE

0

Parity enable

Enables/disables parity generation/checking for the
UART transmitter and receiver. The transmitter generates
proper parity. The receiver checks for proper parity. If the
receiver encounters a bad parity bit, the RPE field is set in
the Serial Channel B/A/C/D Status Register A (see
page 620).

D26

R/W

STOP

0

Stop bits

0

1 stop bit

1

2 stop bits

Determines the number of stop bits in each UART
transmitter.

D25:24

R/W

WLS

00

Word length select

00

5 bits

01

6 bits

10

7 bits

11

8 bits

Determines the number of data bits in each UART data
word.

D23

R/W

CTSTX

0

Activate clear to send

Supports hardware handshaking. When CTSTX is set, the
transmitter operates only when the external CTS signal is
in the active state. An external device, then, can use CTS
to temporarily stall data transmission.

D22

R/W

RTSRX

0

Activate ready to send

Supports hardware handshaking. When RTSRX is set, the
RTS output provides the receiver FIFO almost-full
condition. When the receiver FIFO backs up, the RTS
signal is dropped. The RTS output stalls an external
transmitter from delivering data.

Bits

Access

Mnemonic

Reset

Description

Table 367: Serial Channel B/A/C/D Control Register A

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