Hi all,
I'm struggling with extreamly weird scenario for me. I have a device using LPC2148. I wanted to run USB communication, so I had downloaded HID example code and upload to the device. In uVision debug mode, I can see, that device get a request for Device Descriptor and generates a response writing it to register USBTxData (from specification) / TX_DATA (from example code). How ever, any byte is not sent on a +D -D lines.
I have checked PLL settings and they are correct - also confirmed by appropriate reciving descriptor request - USB block works
I have external power supply, so I did not connect pin P0.23/VBUS to USB connector. It is used to different purposes.
Example code was not modified.
IRQs works as normal.
What else I can check? What can blocks USB to send data out?
Vbus line in USB socket - Yes. Each time I connect USB cable.
Vbus/P0.23 in LPC chip:
- directly from 5V form USB socket - No
- through divider giving 4,42V - Yes
- directly from 3,3V - No
This is what errata sheet from this chip says: