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# The Apple 401 Color Plotter | ||
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## General concepts | ||
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The way the 401 interprets a coordinate at any given time depends on the current | ||
viewport and window settings. The "viewport" is a rectangle specified in hardware | ||
absolute coordinates and defines the physical area in which coordinates are resolved. | ||
The "window" defines the virtual coordinates of the drawing area, which are then | ||
mapped to the viewport. | ||
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Commands sent to the 401 are terminated by the ASCII "end of text" delimiter, 0x03. | ||
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### Serial connection | ||
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The 8 DIP switches (SW1-SW8) on the back of the plotter are used to configure the | ||
serial interface. | ||
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SW1 selects the data bits. ON = 7 bits, OFF = 8 bits. | ||
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SW2 selects whether parity is used. ON = no parity bit, OFF = use a parity bit. | ||
If parity is selected, SW3 determines the type of parity bit. ON = odd parity, | ||
OFF = even parity. | ||
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SW4 and SW5 select the number of stop bits: | ||
| SW4 | SW5 | Stop bits | | ||
|------|------|---------------| | ||
| OFF | OFF | 2 stop bits | | ||
| ON | OFF | 1.5 stop bits | | ||
| OFF | ON | 1 stop bit | | ||
| ON | ON | invalid | | ||
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SW6, SW7, and SW8 select the baud rate: | ||
| SW6 | SW7 | SW8 | Baud | | ||
|-----|-----|-----|------------| | ||
| OFF | OFF | OFF | 75 baud | | ||
| OFF | OFF | ON | 150 baud | | ||
| OFF | ON | OFF | 300 baud | | ||
| OFF | ON | ON | 600 baud | | ||
| ON | OFF | OFF | 1200 baud | | ||
| ON | OFF | ON | 2400 baud | | ||
| ON | ON | OFF | 4800 baud | | ||
| ON | ON | ON | 9600 baud | | ||
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**The 401 uses hardware handshaking.** It never returns data to the computer | ||
over the serial line and sets DSR when its internal buffer is full. Sending even | ||
one byte after the DSR line has been set will corrupt the 401's command buffer | ||
and trigger an error. Most USB to RS232 cables will attempt to bundle up several | ||
bytes before transmission, so unless you're sure that your cable can handle it | ||
I recommend flushing the serial connection after every byte and checking the DSR | ||
line yourself. | ||
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## Command Reference | ||
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### Move Absolute (MA) | ||
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``` | ||
MAx,y | ||
``` | ||
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Raise the pen and move the plotter head to the position specified by the x,y coordinates. | ||
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### ??Move relative (MR)?? | ||
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``` | ||
MRx,y | ||
``` | ||
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Raise the pen and move the plotter head to a position offset x,y from its | ||
current position. | ||
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### Draw absolute (DA) | ||
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``` | ||
DAx,y(,x,y..) | ||
``` | ||
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Lower the pen and draw a line from the current position to the position | ||
specified by the x,y coordinates. Continues | ||
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==??Draw relative (DR)??== | ||
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DRx,y(,x,y)* | ||
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lower pen and draw line from current position to an x,y offset. Multiple | ||
offsets may be specified in a single command. | ||
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==Circle (CA)== | ||
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CAr,x,y | ||
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lower pen and draw a circle of radius r centered at x,y. | ||
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==Letter size (LS)== | ||
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LSs | ||
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sets the font size to s | ||
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==Letter rotation (LR)== | ||
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LRtheta | ||
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draw following text rotated by theta | ||
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==Print letters (PL)== | ||
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PLtext | ||
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lower pen and draw specified text at current position | ||
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==Pen select (PS)== | ||
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PSi | ||
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select pen i (where i is in 1-4) | ||
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LT - letter ??? | ||
XT - ? xticks ? | ||
YT - ? yticks ? | ||
CH - ??? | ||
PM - ??? | ||
PS - pen select | ||
PV - ??? | ||
WD - window | ||
AC - arc | ||
LI - ??? | ||
IM - ??? | ||
PK - ??? | ||
RS - ??? | ||
VP - ??? | ||
UL - ??? | ||
SP - ??? | ||
LF - ??? | ||
SL - ??? |
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