VV0670P001 View Datasheet(PDF) - Vision
Part Name
Description
MFG CO.
'VV0670P001' PDF : 36 Pages View PDF
Colour Processor Interface ASIC
2.2.5.7 1284 Device ID Transfers
The CPiA device can return a Device ID string, as defined in IEEE Std 1284, using Nibble Mode Reverse
Channel Transfer. This Device ID is requested by the Microsoft Windows 95/98 operating systems during
their PnP boot processes. It is used to load the approriate device drivers for the hardware attached to the
port.
The device can return two possible Device ID strings dependent on the state of the ID_SELECT pin. This pin
has an internal pull-up resistor which, when not connected, provides a Device ID for a parallel port only CPiA-
based camera module. When pulled low externally, the Device ID will be that which is used for a combined
parallel port and USB module.
The complete Device ID’s returned in these two situations are shown in the table below.
ID_SELECT
Returned Device ID
1(default)
MFG:VLSI Vision Ltd;MDL:PPC2 Camera;CMD:CPIA_1-20;CLS:MEDIA;DES:Parallel Port Camera;
0
MFG:VLSI Vision Ltd;MDL:DUAL-B Camera;CMD:CPIA_1-20;CLS:MEDIA;DES:USB / Parallel Port Camera;
2.2.5.8 Command / Status Transfers
All command and status transfers are preceeded by the negotiation and setup phases as defined in the Std
1284 for the ECP and NIbble modes.
Forward data transfers always use the ECP transfer protocol.
Reverse data transfers use either ECP, or Nibble mode, transfer protocols, depending or whether the host has
a bi-directional port or not.
Channel addressing and RLE as defined in the ECP spec are not used by CPiA.
Data is transfered in 8 byte packets, each packet being preceeded by the 1284 negotiation and setup
sequences, and terminated with a 1284 termination sequence.
Commands are passed to CPiA in a single 8 byte packet, termed a command transfer. This can optionally be
followed by the transfer of a data transfer. Bytes within the command packet are used to specify whether a
data packet is to follow, and its direction.
Most commands are not accompanied by data packets.
The following diagram, Figure X.Y, shows the activity that occurs on the parallel port control and status lines
during a command transfer to CPiA, via a Forward ECP Mode transfer. NOTE - The actual data is carried on
the 8 data lines, which are not shown on the diagram.
V:\apps\cpia\docs\cpia datasheet\cpia_datasheet4.fm
02/07/98
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