Hi! Allowable clock tolerance for full speed USB is +/- 0.25%. Without the Active Clock Tuning (ACT) Module, the internal oscillator doesn't meet that accuracy. Did you activate that modue?
Greets, Kiste Am Freitag, 19. Februar 2021, 07:45:43 MEZ hat vsurducan <[email protected]> Folgendes geschrieben: Thx Rob. You point out the problem well. I'm testing with PIC18F25k50. With 16MHz HS and 3x PLL the USB communication works ok. However with 16MHz INTOSC and PLL, I continuously get the same error "USB device has a malfunction..." WIN does not read the USB descriptor, perhaps because of wrong or unstable frequency on the USB module. On the other hand, PIC18F25K50 USB oscillator description is quite weird: For low speed, USB module must have a 6MHz clock by setting the LS48MHz bit (table 3.6 page 47 DS30000684B datasheet). This is crystal clear. For high speed, USB module must have 48MHz, but no description of how to do that is given (table 3.7, the same page). Fig.1 at page 29 shows the clock structure for USB. What has to be set to have a 48MHz USB clock? I will dig more... On Thu, Feb 18, 2021 at 8:22 PM Rob CJ <[email protected]> wrote: > > > Hi Vsurducan, > > > > > The datasheet of the 18f14k50 states this: > > > > > "For full-speed USB operation, a 48 MHz clock is required for the USB >Module. To generate the 48 MHz clock, only two oscillator modes are allowed: > > -) EC High-Power mode > > -) HS Mode" > > > > > I have seen a sample file that runs at 48 MHz but uses the internal >oscillator, see 18f67j50_usb_serial.jal. > > > > > I am not sure if this answers your question. > > > > > Kind regards, > > > > > Rob > > > > > > > > > > > > ________________________________ > Van: [email protected] <[email protected]> namens vsurducan > <[email protected]> > Verzonden: donderdag 18 februari 2021 15:09 > Aan: [email protected] <[email protected]> > Onderwerp: [jallib] USB issue > > > > > > Hi, I've seen two complete examples of using USB libraries; both are > bootloaders, one using 18F4450 and the other 18F14k50. > > Both are using USB clocks at 48MHz, so USB runs in full speed mode. Both use > an external crystal in HF mode and PLL to acquire 48MHz clock. > > The bootloader for 18F4450 works ok also on 18F2550 without any issue...I've > tested a while ago. > > > > I'm trying to use usb_serial on a 18F25k50 running in INTOSC mode 48MHz > (16Mhz and 3x PLL) and USB module in low speed mode (6MHz). The computer > does not read OK the USB device descriptor when the PIC is connected. This > can be a communication issue but also a software error. > > > > Anyone know if full speed is mandatory for these USB libraries? > > Maybe there is another example of using USB which I missed? > > > > thank you all, > > > > > > > -- > You received this message because you are subscribed to the Google Groups > "jallib" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/jallib/CAM%2Bj4qsKAjTVPRWpNFcj4FpXQLWR2fG72JvHwj%3D4r8snkUdTwA%40mail.gmail.com. > > > > > -- > You received this message because you are subscribed to the Google Groups > "jallib" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/jallib/AM0PR07MB62412A9D03749696FCE18131E6859%40AM0PR07MB6241.eurprd07.prod.outlook.com. > -- You received this message because you are subscribed to the Google Groups "jallib" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/jallib/CAM%2Bj4qsprDUG6EeUGvFKy4UZ1WozYrAzbSmg%2BcAob5DFFENz_w%40mail.gmail.com. -- You received this message because you are subscribed to the Google Groups "jallib" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/jallib/1593689859.146178.1613726536055%40mail.yahoo.com.
