Denso BHT-7500S, BHT-7500W user manual Transmission Code and Bit Order, Vertical Parity

■Transmission Code and Bit Order

All characters should be coded to 7- or 8-bit code for data transmission. The standard data exchange code of the BHT is JIS 7- or 8-bit code. The transmission bit order is LSB (Least significant bit) first.

What follows is an example for transmitting character A (41h, 01000001b) coded to JIS 8-level code with an even parity and a single bit each for start and stop bits.

LSB

1

0 0 0 0 0

1

MSB

0 0

Start bit Stop bit

Parity bit

■Vertical Parity

A vertical parity bit is a redundancy bit which is added to every character to be transmitted in order to check that data has been transmitted accurately. The parity bit should be set to "1" or "0" depending upon the parity parameter setting, to make the number of set bits in the character even or odd. The receiver counts the number of set bits in the transmitted character code to make sure that it has the selected number (even or odd) of set bits.

The vertical parity bit is positioned immediately following the MSB (Most signifi- cant bit) as shown below.

LSB						MSB
b0	b1	b2	b3	b4	b5	b6

(For 7-bit data)

Vertical parity bit

LSB							MSB
b0	b1	b2	b3	b4	b5	b6	b7

(For 8-bit data)

Vertical parity bit

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