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Registered Member #1143
Joined: Sun Nov 25 2007, 04:55PM
Location: Vilnius, Lithuania
Posts: 721
Hello, i am making car headunit from Lenovo Phab plus.
I want to use USB DAC for better audio quality , but sound is not buffered, so if i connect DAC and USB Flash to hub, it start to jitter badly ( sharp noise do to lack of samples when hub switch to USB FLASH)
So here is the problem, i need to enable one USB device with microcontroller ( i will have FLASH, USB Camera, USB DAC, and also STM32 USB as HID) HID and DAC is 12MHz so i could use analog switch from Analog devices, but flash and USB camera runs on 480MHz, so i can't use any solid state analog switch.
So question, how can i have full speed USB HUB, where i can enable USB channel by mcu ? (only single channel at the time)
( main problem is, when i go into reverse gear, it must disconnect dac from tablet, and connect camera that runs at 480Mbps)
Registered Member #2906
Joined: Sun Jun 06 2010, 02:20AM
Location: Dresden, Germany
Posts: 727
After reading it 10x.... i have still no idea how your system looks like. But at one point you say that oyu cant use an analog usb multiplexer due to 480MHz Highspeed-USB.
Are you sure Highspeed-USB-Multiplexers like this cant do the job? The 480MHz is not really a problem here. I am sure there are also 4:1 available... you could also use 2 of the multiplexers since there is an Enable pin per Chip.
Your audio problem: do you have any influence to the endpoint buffer size? If its 16 Byte.. then yeah.. but if 512 Byte is supported.. maybe its just not enabled? But i am just guessing.
Registered Member #2906
Joined: Sun Jun 06 2010, 02:20AM
Location: Dresden, Germany
Posts: 727
If thats the right stuff, then: i just googled for "high speed usb 2.0 switch" it brings up some other ICs too - TI is not the only company. Maybe you find even better ICs that suit your needs Good luck!
Infact: TI has a whole procut line for this: Fairchild is in the mix too: just go one up in the hirarchy... Same with NXP, but their website sucks OnSemi And MAXIM never lets a chance go to make an expensive IC:
Registered Member #1143
Joined: Sun Nov 25 2007, 04:55PM
Location: Vilnius, Lithuania
Posts: 721
DerAlbi wrote ...
If thats the right stuff, then: i just googled for "high speed usb 2.0 switch" it brings up some other ICs too - TI is not the only company. Maybe you find even better ICs that suit your needs Good luck!
Infact: TI has a whole procut line for this: Fairchild is in the mix too: just go one up in the hirarchy... Same with NXP, but their website sucks OnSemi And MAXIM never lets a chance go to make an expensive IC:
Damn, i was googling HUB instead switch :) I always can count on this forum to get answer :D
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4:1 MCU controled USB "HUB"
Good luck!