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Hi,
I'll start a new project with an ARM7 or Cortex-M3 controller (including flash and ram as well as usb).
I'll add some peripherals to the controller - touch screen controller and led controller via spi, one encoder and 4 buttons via gpio. All information (button pressed, touch coordinates and so on) will be transferred via usb to a computer (intel processor).
I think it's enough to get these information every 1ms. Is an STM32F cortex-m3 controller fast enough to proceed all these requests? I'm not sure (never worked with usb so far) if the performance for usb 2.0 is enough...
Maybe someone of you can give me some information / perofmance suggestions...
best regards Herbert
I am not sure your host will be able to start a new request to the device every millisecond. However, I am working on a system based on a LPC2478 at 64[MHz] that can be polled via a CDC connection every 125[ms] without a problem (while doing other things, too).
The cortex-M3 processor will be not the host controller - it will be a normal device controller. The host controller is a normal PC computer with intel atom processor.
I don't know much about this. But I think that, The host controller is a normal PC computer is just what Tamir worried about.
1 ms response time is OK for an Embedded/Real-time system, but it might not be OK for Windows/Linux/Mac-OS.
>i>1 ms response time is OK for an Embedded/Real-time system, but it might not be OK for Windows/Linux/Mac-OS.
ok then I missunderstood Tamir. That means the controller is able to perform these usb transfers every 1ms, but maybe the embedded host controller is not able to be as fast as the cortex-m3.
But a normal mouse is also working with a 1ms time intervall (at a windows or linux computer).