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9.3.2 Data Composition
1)
Start bit
1/2 bit past the line dropping from MARK to SPACE, a status reading is taken again.
If the reading is SPACE, a start bit is recognized, but if it is MARK, it is not taken as a start bit.
This is not regarded as an error, but the search for the start bit is performed once again.
2)
Data bit and parity bit
Data bits and parity bits are the data of the bits in question, which are represented by the state at the
time sampling is performed. This is accomplished at time intervals equal to one bit in length, beginning
from the middle of the start bit. The order of the bits is, starting with the bit closest to the start bit, bit-0,
bit-1......, parity bit. (Note: data bits are based on "one point sampling".)
3)
Stop bit
The stop bit consists of one or more bits at "mark" level. When "space" level is detected for a stop bit, a
framing error occurs.
9.3.3 Error Detection
The printer detects Parity, Framing and Overrun Error. When any error is detected, the data is
converted into (7FH).
1)
Framing Error
Framing error occurs when SPACE signal is checked out at STOP BIT.
And the data is converted into (7FH).
2)
Parity Error
When parity check is designated and if the parity error is detected, the data is converted into (7FH).
3)
Overrun error
When an overrun error is detected, the data is converted into (7FH).
4)
Other errors
When trouble is detected in the printer mechanism, the SEL / ALARM lamp goes on, the buzzer is
sounded, the FAULT signal is output, and the DTR signal becomes BUSY. After the cause of the trouble
has been corrected, the SEL / ALARM lamp can be turned off by pressing the SEL switch or by making
RESET = "0". When the printer is put ONLINE, data receiving restarts.
CITIZEN
[1] Start bit
[2] Data bits (and parity bit)
[3] Stop bit (1 bit or more)
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iDP3540/3541 User's Manual
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