Packet Details; The Initialization And Connection Packet; Print Instruction Packet - Nintendo GAME BOY Programming Manual

4. PACKET DETAILS

4.1 The Initialization and Connection Packet

This packet is used to initialize the printer and check the connection. If the Game Boy sends a packet
for checking the printer connection and a printer is connected, it returns a 2-byte status code and
initializes for the start of print processing. This packet must always be sent when the Game Boy starts
to access the printer. It allows transferred data to be invalidated (reset).
Actual Data
88 33 01
PA
This packet has no data section.
Normal status: 81h and 00h (For more information, see Section 3, Communication Data
Definitions.)
Not connected: FFh and FFh.

4.2 Print Instruction Packet

Used for print instructions for single-sheet mode and copy mode (for specifying the number of sheets).
Example:
88 33 02
PA
Data: Byte 1 specifies the number of sheets.
Data: Byte 2 indicates the number of line feeds. Higher-order 4 bits represents the number of feeds
* 1 feed = 2.64 mm
Data: Byte 3 holds the palette values.
Data: Byte 4 is the print density adjustment.
When printing continuous images from multiple screens, setting the number of line feeds to 0 after
one screen's worth of data is printed (9 data packets and a data-end packet) enables printing to be
continued from one image to the next without a break.
00 00 00 01
Header Checksum
00 04 00 01
Header
00 00 00
Dummy
13 E4 40 3D
Data Checksum
0-255 (1 in the example). 0 means line feed only.
before printing.
Lower-order 4 bits represents the number after
printing. Each value is 00h-0Fh.
Default is 00. Palettes are defined by every 2 bits
beginning from high bit. (See Chapter 2, Section
2.3, Character RAM.)
00h-7Fh. Default values are 40h and 80h or
greater.
00 < 40h < 7Fh
-25% 0% +25%
241
Chapter 9: Pocket Printer
01 00 00
Dummy