If there's another thread that describes this, I apologize. I had to hunt a bit to find everything needed to get it working, so I thought I'd paste it all here so future miners can save some time:
If using
version 3.1.1, it needs a driver to make the USB devices visible as COM devices (a UART driver). Follow these instructions:
1 - As listed in the FPGA-README doc with cgminer, install this driver for your little USB miners:
http://sourceforge.net/projects/libwdi/files/zadig/Note the "latest" link on the top of the page isn't what you want! You want the one that starts with Zadig. As of this writing, the version is: zadig_v2.0.1.160.7z
Also note you will need 7zip to unzip it.
2 - After it installs, reboot as windows tells you do. Wait until Zadig tells you its done installing, windows may ask you before Zadig says it is done.
Note that you only have to do it once for all your miners, not once for each one.
Also note that the renaming doesn't seem to work right, or is not intuitive. I tried renaming one and it didn't work.
3 - Install the UART to COM drivers from here:
http://www.silabs.com/products/mcu/Pages/USBtoUARTBridgeVCPDrivers.aspx4 - Check device manager, you should see items under your ports section now, with the COM port assigned for each one.
5 - Run cgminer-nogpu with these options:
--icarus-options 115200:1:1 --icarus-timing 3.0=100 -S COMx -S COMy -S COMz -S COMetc
For my 7 miners, I'm using:
--icarus-options 115200:1:1 --icarus-timing 3.0=100 -S COM3 -S COM4 -S COM5 -S COM6 -S COM7 -S COM8 -S COM9
Note that if you have more than 7, you will probably need to use this format for the COM ports to recognize COM10 and beyond:
-S \\.\COM3 -S \\.\COM4 -S \\.\COM5 -S \\.\COM6 -S \\.\COM7 -S \\.\COM8 -S \\.\COM9 -S \\.\COM11 -S \\.\COM12 -S \\.\COM13
If using
version 3.4.2 (or higher), you do NOT want the UART driver, so follow these instructions:
1 - As listed in the FPGA-README doc with cgminer, install this driver for your little USB miners:
http://sourceforge.net/projects/libwdi/files/zadig/Note the "latest" link on the top of the page isn't what you want! You want the one that starts with Zadig. As of this writing, the version is: zadig_v2.0.1.160.7z
Also note you will need 7zip to unzip it.
2 - After it installs, reboot as windows tells you do. Wait until Zadig tells you its done installing, windows may ask you before Zadig says it is done.
Note that you only have to do it once for all your miners, not once for each one.
Also note that the renaming doesn't seem to work right, or is not intuitive. I tried renaming one and it didn't work.
3 - Run cgminer-nogpu with whatever options you need to point to your pools. No other parms are necessary.
For my 25 miners, I'm using:
cgminer-nogpu.exe -c "cgminer.conf"
Version 3.1.1 gives me about 333mh/s on Win7x64. Version 3.4.2 gives me about 335mh/s. I seem to get less hardware errors on 3.4.2 as well.
If you need a configuration file for pools, here is what I use:
{
"pools" : [
{
"url" : "http://stratum.btcguild.com:3333",
"user" : "user",
"pass" : "password"
},
{
"url" : "http://stratum.ozco.in:3333",
"user" : "user",
"pass" : "password"
},
{
"url" : "http://192.168.0.194:8332",
"user" : "user",
"pass" : "password"
}
]
}
Note that the first two pools are true pools, the third one is a local instance of bitcoind.
M
***UPDATED 9/8/2013 to include info on 3.4.2 and an example of cgminer.conf with pools.
Have only been able to get 3.1.1 working with the SiLabs driver 
