ColdFire/68K Microcontrollers and ProcessorsのトピックRe: MCF51JM64 interrupt issue

MCF51JM64 interrupt issue

CSoto — Tue, 26 Oct 2010 02:29:12 GMT

Hi,

I'm trying to integrate the CMX generic HID demo code into my own application and board to enable USB communication with the PC host.

When I look at the MCF_USB_INT_STAT register after an interrupt has been raised, I always get the USB_RST bit, but also the SOF_TOK bit even though the last one hasn't been enabled in the init code.

I should say that the HID demo runs fine in my board, so it shouldn't be a hardware problem. Any clues? I'm totally stuck right now.

Thanks in advance

Re: MCF51JM64 interrupt issue

CSoto — Wed, 27 Oct 2010 01:49:57 GMT

After some research, it seems the problem is that I can't get any TOK_DNE interrupt, so the hosts generates RESETs until it finally gives up and stops sending any message.

I'm using PE to initialize hardware, and I think the CLK settings are right (I've got a 12MHz external clock, and the PLL output frequency is 48MHz to feed the USB peripheral) but right now I'm not quite sure I've set everything right.

I also thought it could be related to the other interrupts, but right now I'm only using 3 more (TPM2, SCI1 and I2C2)

I'll keep searching, but any help would be greaty appreciated.

Re: MCF51JM64 interrupt issue

SecondTechCo — Wed, 06 Mar 2013 14:39:28 GMT

I am wondering how this turned out. I am using the CDC sample program and freescale stack and find continuous interrupts generated anytime the usb cable is plugged in. The interrupt is SOF_TOK. IS this necessary in the USB stack ?

Re: MCF51JM64 interrupt issue

JimDon — Wed, 06 Mar 2013 14:58:04 GMT

Yes:

Start of Frame Packets

The SOF packet consisting of an 11-bit frame number is sent by the host every 1ms ± 500ns on a full speed bus or every 125 µs ± 0.0625 µs on a high speed bus.

USB is a polled protocol. The host asks device if it has anything.

Re: MCF51JM64 interrupt issue

SecondTechCo — Wed, 06 Mar 2013 15:05:30 GMT

This would seem to bog down a real time system with a lot of interrupts wouldnt it ? Does each device need to respond back to the host even if it has nothing?

Re: MCF51JM64 interrupt issue

SecondTechCo — Wed, 06 Mar 2013 15:14:09 GMT

IE can I turn off the interrupt so it doesn't bog down my micro and then respond only when I have something.

Re: MCF51JM64 interrupt issue

JimDon — Wed, 06 Mar 2013 15:39:29 GMT

You may be able to ignore SOF, I am not 100% sure if you must ack this packet.

But if you ignore all polls, for more than 3ms you will be "suspended".

You need to balance things carefully when using native USB.

Re: MCF51JM64 interrupt issue

SecondTechCo — Wed, 06 Mar 2013 15:44:23 GMT

Thanks. You have been very helpful. Is there another way to use USB ? IE Non native ?

Re: MCF51JM64 interrupt issue

JimDon — Wed, 06 Mar 2013 16:37:25 GMT

I've used the FT232H connected to a CFV2 8 bit parallel interface. I send the data on a non-interrupt thread, so real time keeps running. Since it hi speed usb, you can send data at a much higher rate. Note that the 80Mhz V2 maxes out at about 1MB, but realistically 700KB to allow other things to happen.

Also, no issues with device drivers, as FTDI provides all that.

FT232H