LPC47N237 Datasheet, PDF (54/138 Pages) SMSC Corporation – 3.3V I/O CONTROLLER FOR PORT REPLICATORS AND DOCKING STATIONS

3.3v I/O Controller for Port Replicators and Docking Stations
NAME
nAutoFd
(HostAck)
nFault
(nPeriphRequest)
nInit
nSelectIn
TYPE
O
I
O
O
DESCRIPTION
Requests a byte of data from the peripheral when asserted, handshaking
with nAck in the reverse direction. In the forward direction this signal
indicates whether the data lines contain ECP address or data. The host
drives this signal to flow control in the reverse direction. It is an
"interlocked" handshake with nAck. HostAck also provides command
information in the forward phase.
Generates an error interrupt when asserted. This signal provides a
mechanism for peer-to-peer communication. This signal is valid only in
the forward direction. During ECP Mode the peripheral is permitted (but
not required) to drive this pin low to request a reverse transfer. The
request is merely a "hint" to the host; the host has ultimate control over
the transfer direction. This signal would be typically used to generate an
interrupt to the host CPU.
Sets the transfer direction (asserted = reverse, deasserted = forward).
This pin is driven low to place the channel in the reverse direction. The
peripheral is only allowed to drive the bi-directional data bus while in ECP
Mode and HostAck is low and nSelectIn is high.
Always deasserted in ECP mode.
9.6.2 Register Definitions
The register definitions are based on the standard IBM addresses for LPT. All of the standard printer ports
are supported. The additional registers attach to an upper bit decode of the standard LPT port definition to
avoid conflict with standard ISA devices. The port is equivalent to a generic parallel port interface and may
be operated in that mode. The port registers vary depending on the mode field in the ecr. The table below
lists these dependencies. Operation of the devices in modes other that those specified is undefined.
Table 9.4 - ECP Register Definitions
NAME
data
ecpAFifo
dsr
dcr
cFifo
ecpDFifo
tFifo
cnfgA
cnfgB
ecr
ADDRESS (NOTE 9.6)
+000h R/W
+000h R/W
+001h R/W
+002h R/W
+400h R/W
+400h R/W
+400h R/W
+400h R
+401h R/W
+402h R/W
ECP MODES
000-001
011
All
All
010
011
110
111
111
All
FUNCTION
Data Register
ECP FIFO (Address)
Status Register
Control Register
Parallel Port Data FIFO
ECP FIFO (DATA)
Test FIFO
Configuration Register A
Configuration Register B
Extended Control Register
Note 9.6 These addresses are added to the parallel port base address as selected by configuration register or
jumpers.
Note 9.7 All addresses are qualified with AEN. Refer to the AEN pin definition.
Revision 0.3 (10-26-04)
Page 54
DATASHEET
SMSC DS – LPC47N237