PORTS Forum
Ports and Interfaces => USB => Topic started by: Edio on March 27, 2019, 01:27:01 pm
-
Hi,
I got a strange behavior taht I coul not figure out yet
I got an arrangement with: one AT-SAMD11 low speed HID keyboard, one GL850G HUB and one full speed finger print reader.
When connected, everybody enumerate ok and the keyboard works as spected, but when I start readind the finger print reader the keyboard crashes.
If instead of my keyboard I use another keyboard or mouse, they work normaly, which sugests that the problem might be the keyboard.
If I switch the AT-SAM keyboard from low speed to full speed, they work normaly as well, wich sugests that the problema might be a AT-SAM low spped HID keyboard.
If I use a HUB other than GL850G everything wortks fine even with the low speed implementation, which sugests that it is a impatibility of GL850G and AT-SAM low Spped HID.
looking with a USB hardawre monitor I see resets/disconnection in the line with the low speed implementation till it dies, with the full speed implementation I see transactions that the device copes with.
When I am not using AT-SAM nor GL850G I see no disturbunce in the keyboard side of the HUB when I am readind the finger print reader, wich I think is the right behavior.
It seens that the full speed data means something to the low speed AT-SAM, but I dont have a clue right now, I will appreciatte any direction given.
-
Assuming these are commercial, off-the-shelf products, not devices you are developing, I suggest using the hardware configuration that you've found works. You don't have access to the device internals and thus no way to fix them.
-
I am sorry if I was not clear, I am developing the AT-SAM keyboard as I mentioned that I changed from low to full speed (recompiling the Firmware).
-
Too many low-speed devices connected directly to the host?
Be sure the VID and PID combination for the keyboard doesn't match the values used by another device.
Looking at what happens before the resets (what is causing them?) might offer a clue.
-
I got an arrangement with: one AT-SAMD11...
I would be careful of what upstream hubs you are using.
I'm making an assumption here that may be completely unfounded.
Years ago when Atmel came out with their first USB AVR I found that they worked with Intel hubs and did not work with NEC hubs (the PC motherboard had both).
I reported the problem back to Atmel in the hopes they would fix it.
I don't know if they ever did.
My assumption is that the SAMD11 might somehow contain concepts from that same broken legacy hardware/code of long ago.
I've lost to much blood to the Bleeding Edge of technology... :-(
-
Yes, thanks bpaddock, it could just be a malfunctioning hub.
-
I'm sorry, I had a health problem and left this problem berind.
I have a feeling that this problem may be related to a HUB with single TT, I'll give a multi TT HUB (GL852G) a change and see what happens.