CH 12 BOF – The last channel 12 loaded is used as the Bottom–of–Form (BOF) channel and has sig- nificance when using the printer skip–over perforation feature. When skip–over perforation is en- abled, paper skips from BOF to TOF only if at the BOF position. If a channel search moves paper past the BOF position but before the TOF position, no skip–over perforation will occur.

Table 5–4. DVFU Channel Assignment

Binary

First Data Byte

 

Binary

Second Data Byte

 

Channel #

 

 

Value

Bit #

Value

Bit #

Channel #

 

 

 

 

 

 

128

8

X (don’t care)

128

8

X (don’t care)

 

 

 

 

 

 

64

7

X (don’t care)

64

7

X (don’t care)

 

 

 

 

 

 

 

32

6

6

 

32

6

12 – BOF

 

 

 

 

 

 

 

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

 

 

 

 

 

 

 

End Load Code – 6F Hex

The DVFU end load code is 6F (hex) with the PI line high. This terminates the DVFU memory load routine.

Using the DVFU

The VFU LOADED indicator on the control panel glows when the DVFU program has been enabled and loaded. Sending an appropriate channel code to the printer causes any data in the buffer to print and slew the paper to the next line on the form having the specified channel number assigned in DVFU memory. To recognize a data byte as a DVFU channel instruction, the following criteria must be met:

1.The PI line must be enabled and set high; and

2.Data bit 5 must be 0 (not set).

Given these conditions, the lower four bits of a byte will specify the DVFU channel number. Table 5–5 lists DVFU channels and their equivalent data bytes.

5–8

Vertical Format Units

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Image 82
Printronix P3000 Series manual End Load Code 6F Hex, Using the Dvfu