LPC47M192-NW Standard Microsystems (SMSC), LPC47M192-NW Datasheet - Page 93

• Manufacturer Part Number: LPC47M192-NW
• Manufacturer: Standard Microsystems (SMSC)

Specifications of LPC47M192-NW

• Lead Free Status / RoHS Status: Compliant

tFifo (Test FIFO Mode)
ADDRESS OFFSET = 400H
Mode = 110
Data bytes may be read, written or DMAed to or from the system to this FIFO in any direction. Data in the tFIFO will
not be transmitted to the to the parallel port lines using a hardware protocol handshake. However, data in the tFIFO
may be displayed on the parallel port data lines.
The tFIFO will not stall when overwritten or underrun. If an attempt is made to write data to a full tFIFO, the new data
is not accepted into the tFIFO. If an attempt is made to read data from an empty tFIFO, the last data byte is re-read
again. The full and empty bits must always keep track of the correct FIFO state. The tFIFO will transfer data at the
maximum ISA rate so that software may generate performance metrics.
The FIFO size and interrupt threshold can be determined by writing bytes to the FIFO and checking the full and
serviceIntr bits.
The writeIntrThreshold can be determined by starting with a full tFIFO, setting the direction bit to 0 and emptying it a
byte at a time until serviceIntr is set. This may generate a spurious interrupt, but will indicate that the threshold has
been reached.
The readIntrThreshold can be determined by setting the direction bit to 1 and filling the empty tFIFO a byte at a time
until serviceIntr is set. This may generate a spurious interrupt, but will indicate that the threshold has been reached.
Data bytes are always read from the head of tFIFO regardless of the value of the direction bit. For example if 44h,
33h, 22h is written to the FIFO, then reading the tFIFO will return 44h, 33h, 22h in the same order as was written.
cnfgA (Configuration Register A)
ADDRESS OFFSET = 400H
Mode = 111
This register is a read only register. When read, 10H is returned. This indicates to the system that this is an 8-bit
implementation. (PWord = 1 byte)
cnfgB (Configuration Register B)
ADDRESS OFFSET = 401H
Mode = 111
BIT 7 compress
This bit is read only. During a read it is a low level. This means that this chip does not support hardware RLE
compression. It does support hardware de-compression.
BIT 6 intrValue
Returns the value of the interrupt to determine possible conflicts.
BIT [5:3] Parallel Port IRQ (read-only)
to Table 44B
BITS [2:0] Parallel Port DMA (read-only)
to Table 44C
ecr (Extended Control Register)
ADDRESS OFFSET = 402H
Mode = all
This register controls the extended ECP parallel port functions.
BITS 7,6,5
These bits are Read/Write and select the Mode.
SMSC DS – LPC47M192
Page 93
Rev. 03/30/05
DATASHEET