SCH3112I-NE SMSC [SMSC Corporation], SCH3112I-NE Datasheet - Page 119

• Manufacturer Part Number: SCH3112I-NE
• Description: LPC IO with 8042 KBC, Reset Generation, HWM and Multiple Serial Ports
• Manufacturer: SMSC [SMSC Corporation]

LPC IO with 8042 KBC, Reset Generation, HWM and Multiple Serial Ports
Datasheet
SMSC SCH311X
Parallel Port Mode Register 2, 0xF1 in Logical Device 3 Configuration Registers) is ‘1’, the TMOUT bit
is cleared on the trailing edge of a read of the EPP Status Register.
Bits 1, 2 - are not implemented as register bits, during a read of the Printer Status Register these bits
are a low level.
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 SLT - 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 - Acknowledge
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 BUSY 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 - Initiate 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.
Bit 4 IRQE - Interrupt Request Enable
The interrupt request enable bit when set to a high level may be used to enable interrupt requests from
the Parallel Port to the CPU. An interrupt request is generated on the IRQ port by a positive going
nACK input. When the IRQE bit is programmed low the IRQ is disabled.
DATASHEET
103
Rev 0.2 (09-28-04)