Lpc2000

Help anyone,

We are in the process of developing a new USB Printer using an 
LPC2148 processor.  

The USB Interface is configured just fine to use EndPoint 2 as a BULK 
Transfer Endpoint and we are using Bi-directional protocol.

Using Keil USB routines which came with the MCB2140 development 
prototyping hardware, we have been able to configure the hardware and 
get the communication start up is fine.  

We have observed the first transaction across EndPoint2 is an IN 
request, coming from the LPC2148.  We are puzzled by this, we would 
have assumed the first transaction would have been an OUT request 
from the Host side.

Is this a setup issue???

Since the application on the LPC2148 has no data to send it is not a 
problem at first start.  However, after a couple of commands have 
been processed, and their has been several USB Nak'd packets a 
problem occurs.

The problem is occurs when the Host sends an OUT Command with the 
expectation of getting Data returned, the USBPrint.sys and 
application is looking for couple of bytes of data to be returned in 
an IN Packet.  The problem is the LPC2148 resends the Last 
Transmission to the Host again, on the IN request prior to the OUT 
command.

Are we missing a setup condition, which configures the (IN before 
OUT) request or (OUT before IN) request in the USB interface or the 
LPC2148 USB controller setup??? 

Is their something which needs to be done to clear out the EndPoint 2 
Transmit data area in ram???

We sure would appreciate some insight from someone.

Keith and Dwight