A maximum of 12 channels can be assigned to one physical line on the form. Two eight-bit data bytes (CVFU characters) are required per line. As shown in Table 5-10, the least significant 6 bits of the first data byte are used to assign channels 1 through 6; the least significant 6 bits of the second data byte are used to assign channels 7 through 12. If a bit is set, the corresponding channel is assigned.

Each line on the form requires two bytes. For lines not requiring a channel identification, the two bytes should not contain channel assignments.

This procedure can be continued for a maximum of 126 lines (252 CVFU bytes). The CVFU memory is cleared if more than 252 bytes are received before the end load code.

CH 1 TOF - The first channel, line 1 of the form, must be assigned channel 1, top-of-form and Channel 2 must not be defined in this first byte (byte one, bit 2 must be 0) or the entire load sequence is ignored and the memory reset. After the memory is loaded, a Form Feed code (FF, 0C hex) will move the paper tothe next channel 1 (top-of-form).

After the channel assignment on the last line of the form, another channel assignment code must be sent with the top-of-form bit set (called the •dummy TOF"). This channel assignF ment code does not count as a line of the form. All data received after the dummy TOF will be ignored until the end load code is received. Data received after the the dummy TOF is counted as part of the maximum allowed (126 lines, 252 bytes).

CH 2 VT - Channel 2 is used as the vertical tab channel. After the memory is loaded, a VT code (0B hex) will move the paper to the next channel 2. If a VT code is received but channel 2 is not loaded, the paper will advance to the next TOF position. If a VT code is received but the CVFU is not selected or not loaded, a s8

ingle line feed occurs.

End Load Code - 1E Hex

The CVFU end load code is 1E hex. This terminates the CVFU memory load routine.

Table 5-10. CVFU Channel Assignment

Binary

FIRST DATA BYTE

Binary

SECOND DATA BYTE

Value

Bit #

Channel #

Value

Bit #

Channel #

128

8

X (don't care)

128

8

X (don't care)

64

7

set high (1)

64

7

set high (1)

 

 

 

 

 

 

 

32

6

6

 

32

6

12

 

 

 

 

 

 

 

16

5

5

 

16

5

11

 

 

 

 

 

 

 

8

4

4

 

8

4

10

 

 

 

 

 

 

 

4

3

3

 

4

3

9

 

 

 

 

 

 

 

2

2

2

- VT

2

2

8

 

 

 

 

 

 

 

1

1 (LSB)

1

- TOF

1

1 (LSB)

7

 

 

 

 

 

 

 

5-14

Vertical Format Units

Page 94
Image 94
Printronix P9000 Series manual End Load Code 1E Hex, First Data Byte, Second Data Byte