Citizen Systems iDP3421, iDP3423, iDP3420 user manual Data Configuration

iDP3420/3421/3423 User ’s Manual

10.3.2Data Configuration

t

Mark

b0, b1, b2, • • • •

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.

35 CITIZEN