Hi, FBL
Thank you for your reply. Yes, my board entered the ESOF interrupt without losing any SOF. What I mean is that from the USB BUS waveform, there was no loss of SOF, but from the MCU, the SOF interrupt was periodically lost, with a period of about 300ms. Therefore, I suspect that the MCU did not detect SOF, which caused the ESOF interrupt. I don't know why the MCU intermittently did not detect SOF. I used the STM32H5 Nucleo-64 board (MB1814), and I have reproduced this issue on different computers. The code was ported from the USB package of STM3210E.
The following are the interrupt handling codes for SOF and ESOF in the USB interrupt function. In the code, I used the variable esof_resetcount to limit the number of times the device initiates USB RESET during ESOF, otherwise the device will continuously initiate USB RESET
/*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*/
#if (IMR_MSK & ISTR_SOF)
if (wIstr & ISTR_SOF & wInterrupt_Mask)
{
_SetISTR((uint16_t)CLR_SOF);
bIntPackSOF++;
printf("*");
#ifdef SOF_CALLBACK
SOF_Callback();
#endif
}
#endif
/*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*/
#if (IMR_MSK & ISTR_ESOF)
if (wIstr & ISTR_ESOF & wInterrupt_Mask)
{
uint32_t fnr = GetFNR();
/* clear ESOF flag in ISTR */
_SetISTR((uint16_t)CLR_ESOF);
printf("e");
if ((fnr&FNR_RXDP)!=0 && ++esof_resetcount < 1000)
{
// esof_resetcount = 0;
/* increment ESOF counter */
esof_counter ++;
// /* test if we enter in ESOF more than 3 times with FSUSP =0 and RXDP =1=>> possible missing SUSP flag*/
if ((esof_counter >3)&&((_GetCNTR()&CNTR_FSUSP)==0))
{
// /* this a sequence to apply a force RESET*/
/*Store CNTR value */
wCNTR = _GetCNTR();
/*Store endpoints registers status */
for (i=0;i<8;i++) EP[i] = _GetENDPOINT(i);
/*apply FRES */
wCNTR|=CNTR_FRES;
_SetCNTR(wCNTR);
/*clear FRES*/
wCNTR&=~CNTR_FRES;
_SetCNTR(wCNTR);
/*poll for RESET flag in ISTR*/
while((_GetISTR()&ISTR_RESET) == 0);
/* clear RESET flag in ISTR */
_SetISTR((uint16_t)CLR_RESET);
/*restore Enpoints*/
for (i=0;i<8;i++)
_SetENDPOINT(i, EP[i]);
printf("r");
esof_counter = 0;
}
}
else
{
esof_counter = 0;
}
/* resume handling timing is made with ESOFs */
Resume(RESUME_ESOF); /* request without change of the machine state */
#ifdef ESOF_CALLBACK
ESOF_Callback();
#endif
}
