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2 data configuration – Citizen Systems iDP3420 User Manual

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iDP3420/3421/3423 User’s Manual

35

CITIZEN

10.3.2

Data Configuration

t

Mark

b

0

, b

1

, b

2

,

• • • •

Space

(1)

(2)

(3)

(1) Start Bit

(2) Data Bit (+ Parity Bit)

(3) Stop Bit (1 or More)

(1) Start bit

After a lapse of 1/2 bit from a mark-to-space fall edge, the state is read again, and if it is a space, it is

recognized as the start bit.

If it is a mark, it is assumed neither the start bit nor an error, and it is

attempted to detect the start bit again.

(2) Data bit + parity bit

The data bit and parity bit are sampled for 1 bit worth of time from the 1/2 start bit.

The then state

is assumed the data for the corresponding bit.

A sequence of the bits are named Bit 0, Bit 1, ...,

parity bit, starting from the one closest to the start bit.

(3) Stop bit

The stop bit is a mark level of 1 bit or more.

If a space is detected in detecting the stop bit, a

framing error results.