Apple LaserWriter Pro 630 Envelope Feeder Specifications download pdf (Page 81)

CHAPTER 3

LaserWriter Pro Software

SCC Operator Encoding 69

setsccbatch 3

setsccinteractive 3

SCC Operator Encoding 3

The serial communications controller (SCC) operators use a 1-byte options argument that

holds four SCC encoded parameters: stop bits, data bits, ﬂow control, and parity. The

argument is an integer parameter with values in the range 0–255. Table 3-24 lists the bit

values for the compatibility operators options byte.

In PostScript Level 1, the data bits and parity bit interact in a nonorthogonal way, to

produce a table of possible choices for data and parity. The choices include many

commonly required methods of sending data. The Standard data bits setting provides

compatibility with earlier versions of the PostScript Level 1 SCC operators. A standard

setting could always be achieved with either a 7-bit or an 8-bit data setting.

In PostScript Level 2, there are parameters analogous to those given earlier for

%Serial% and %SerialB% device parameter sets.

The mapping between Level 1 stop bits and ﬂow control and Level 2 StopBits and

FlowControl, respectively, is straightforward and obvious. It is not possible to provide

such a one-to-one correspondence between the Level 1 notion of data bits and parity

and the Level 2 parameters DataBits and Parity. Tables 3-25 and 3-26 show the

conversions between PostScript Level 1 data bits and parity and Level 2 DataBits

and Parity.

Syntax channel baud options setsccbatch –

Deﬁnition This operator sets the communication device parameters for serial

communications. It affects the following settings:

■ %SerialB_NV%, if channel equals 9

■ %Serial_NV%, if channel equals 25

baud and options affect the following device parameters:

■ Baud, StopBits, and FlowControl, which are set

according to the values for baud, stop bits, and ﬂow control.

■ DataBits and Parity, which are set based on the bit

positions deﬁned in Tables 3-25 and 3-26.

Error stackoverflow

Syntax channel baud options setsccinteractive –

Deﬁnition This operator pops the input argument off the stack, and pushes 0 0

onto the stack. It does not perform any operation in this application.

Errors rangecheck, stackoverflow, stackunderflow, typecheck

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Apple LaserWriter Pro 630 Envelope Feeder Specifications Page 81