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MARKING LINE
LEAST
SIGNIFICANT
OATA BIT
START BIT
MESSAGE FLOW
HP 27130B
Par
MARKING LINE
L
L
STOP BIT MAY BE
1 OR 2 BIT TIMES
EVEN OR ODD PARITY
BIT
WHICH MAY OR
MAY NOT BE PRESENT
n-
6 OR 7 FOR 7 OR 8
DATA BITS. RESPECTIVELY
FIGURE 4-1. ASYNCHRONOUS MESSAGE FORMAT
PARITY IN TRANSMITTED OR RECEIVED
OAT
A
There are five parity options available for either transmitted or received data:
no parity
odd parity
even parity
'a'
parity
'I' parity
The first parity option generates neither parity nor will it check for any parity. The character length
specified is the actual data element sent and received.
The second and third parity options cause the generation and detection of parity for the transmitted
and received data, respectively, by the SIO. An additional bit is added to the data element for parity.
The fourth and fifth parity options clear or set the most significant bit of every character transmitted.
For the character length of 7 or 8 bits, the 7th or 8th bit, respectively, of the character will be clear
or set before the character is transmitted. On incoming characters, the force parity bit will be strip-
ped with no checking.
The parity option is programmed by using the
wce,
SF 13.
4-13
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