BIT 3 nERR - nERROR
The level on the nERROR input is read by the CPU as bit 3 of the Printer Status Register. A logic “0” means an error
has been detected; a logic “1” means no error has been detected.
BIT 4 SLCT - PRINTER SELECTED STATUS
The level on the SLCT input is read by the CPU as bit 4 of the Printer Status Register. A logic “1” means the printer
is on line; a logic “0” means it is not selected.
BIT 5 PE - PAPER END
The level on the PE input is read by the CPU as bit 5 of the Printer Status Register. A logic “1” indicates a paper end;
a logic “0” indicates the presence of paper.
BIT 6 nACK - nACKNOWLEDGE
The level on the nACK input is read by the CPU as bit 6 of the Printer Status Register. A logic 0 means that the
printer has received a character and can now accept another. A logic “1” means that it is still processing the last
character or has not received the data.
BIT 7 nBUSY - nBUSY
The complement of the level on the nBUSY input is read by the CPU as bit 7 of the Printer Status Register. A logic 0
in this bit means that the printer is busy and cannot accept a new character. A logic “1” means that it is ready to
accept the next character.
CONTROL PORT
ADDRESS OFFSET = 02H
The Control Port is located at an offset of ‘02H’ from the base address. The Control Register is initialized by the
RESET input, bits 0 to 5 only being affected; bits 6 and 7 are hard wired low.
BIT 0 STROBE - STROBE
This bit is inverted and output onto the nSTROBE output.
BIT 1 AUTOFD - AUTOFEED
This bit is inverted and output onto the nAUTOFD output. A logic “1” causes the printer to generate a line feed
after each line is printed. A logic 0 means no autofeed.
BIT 2 nINIT - nINITIATE OUTPUT
This bit is output onto the nINIT output without inversion.
BIT 3 SLCTIN - PRINTER SELECT INPUT
This bit is inverted and output onto the nSLCTIN output. A logic “1” on this bit selects the printer; a logic “0” means
the printer is not selected.
SMSC DS – FDC37N769
Page 76 of 137
Rev. 02-16-07
DATASHEET
SMSC [ SMSC CORPORATION ]
