Can anyone point to a Silicon Labs app note or perhaps a favorite web based tutorial that would get me started? I'm currently plowing through the 100s of hits that I get from a Google search, but it's slow going trying to weed out the junk.

Thanks,

1. VID/PID (Vendor ID/ Product ID): (in device descriptor)
must be unique to a product. INF file matches VID/PID from the device and device driver on the host.

2. Serial number (in string descriptor)
must be unique to each device. Windows holds the device record according to serial number.

3. USB transfer type: bulk, interrupt and isochronous (ignore control transfer at first)
To select a transfer type fits to your requirement, examine the difference of these transfer type.

in full speed     bulk        interrupt     isochronous
Max packet size   64            64            1023
Max packets/msec  19             1               1
Error retry       yes           yes             no
transfer speed    best effort   guaranteed    guaranteed

To send/receive greater size of data, you must split the data into packet on the firmware.
It is similar to UART. To send greater size of data, UART split it into a byte.
USB split it into packets instead of byte.

4. Difference of OUT (PC -> device) and IN (device -> PC) transfer

Handling of transfer is also similar to UART RX/TX on the firmware.
To start USB IN transfer, load a packet to the buffer (USB FIFO) first, like TX on UART.
USB IN interrupt is evoked when the buffer is empty, also like TX on UART.
However, USB IN doesn't start until host PC polls the device,
though the UART TX starts just after the firmware loads data to buffer.
USB OUT transfer is much similar to UART RX.

USB OUT (PC -> device) - UART RX
- host PC send a packet to device
- the MCU USB engine stores the packet on a buffer (USB FIFO)
- the firmware knows the arrival of the packet by interrupt or polling
- the firmware read out the packet from the USB FIFO

USB IN (device -> PC) - UART TX
- the firmware stores a packet to USB FIFO
- the USB engine waits until the host PC polls the device
- the USB engine sends the packet to the host PC
- the firmware knows the USB FIFO is empty by interrupt or polling
- the firmware stores next packet to USB FIFO

The essence is that's all. USB is so simple as long as you are working on established materials. Buy a kit and fiddle it.

(But once you step in maniac region, like I and Patryk in this topic, you'll see hell of detail. Keep out from this region, if you want to sleep well every day )

Tsuneo

Thanks very much for your informative post. (Thanks also for
spending so much time helping _everybody_ here.) You make it sound easy. I think I can do it.

-- Russ

- Several manufacturers distribute unique PID under their VID. SiLabs also.
MCU Knowledge Base 87271 "Obtaining a Unique PID"

- You can buy a range of PID
VOTI: http://www.voti.nl/shop/catalog.html?USB-PID-10
Mecanique: http://www.mecanique.co.uk/products/usb/pid.html

- To get VID formally from USB.org
1. Become a member of the USB-IF for an annual membership fee of US$4000.
2. Logo licensee for US$2000 for a 2 year term.
3. Pay a one-time fee of US$2000
http://www.usb.org/developers/vendor/

b) How to assign unique serial number to each device

Automatically assigning Serial Numbers
Reporting a Serial Number

Thanks for the extra info.