stm32 usb library

[yujiu]

Posted on September 19, 2011 at 11:45

  function as following,  if xfer_len> hnptxsts.b.nptxfspcavail, then fifo space isn't enough

/** * @brief  USB_OTG_HC_StartXfer : Start transfer * @param  pdev : Selected device * @param  hc_num : channel number * @retval USB_OTG_STS : status */ USB_OTG_STS USB_OTG_HC_StartXfer(USB_OTG_CORE_HANDLE *pdev , uint8_t hc_num) {   USB_OTG_STS status = USB_OTG_OK;   USB_OTG_HCCHAR_TypeDef   hcchar;   USB_OTG_HCTSIZn_TypeDef  hctsiz;   USB_OTG_GNPTXSTS_TypeDef hnptxsts;   USB_OTG_HPTXSTS_TypeDef  hptxsts;   USB_OTG_GINTMSK_TypeDef  intmsk;   uint16_t                 len_words = 0;       uint16_t num_packets;   uint16_t max_hc_pkt_count;     max_hc_pkt_count = 256;   hctsiz.d32 = 0;   hcchar.d32 = 0;   intmsk.d32 = 0;     /* Compute the expected number of packets associated to the transfer */   if (pdev->host.hc[hc_num].xfer_len > 0)   {     num_packets = (pdev->host.hc[hc_num].xfer_len + \       pdev->host.hc[hc_num].max_packet - 1) / pdev->host.hc[hc_num].max_packet;         if (num_packets > max_hc_pkt_count)     {       num_packets = max_hc_pkt_count;       pdev->host.hc[hc_num].xfer_len = num_packets * \         pdev->host.hc[hc_num].max_packet;     }   }   else   {     num_packets = 1;   }   if (pdev->host.hc[hc_num].ep_is_in)   {     pdev->host.hc[hc_num].xfer_len = num_packets * \       pdev->host.hc[hc_num].max_packet;   }   /* Initialize the HCTSIZn register */   hctsiz.b.xfersize = pdev->host.hc[hc_num].xfer_len;   hctsiz.b.pktcnt = num_packets;   hctsiz.b.pid = pdev->host.hc[hc_num].data_pid;   USB_OTG_WRITE_REG32(&pdev->regs.HC_REGS[hc_num]->HCTSIZ, hctsiz.d32);       hcchar.d32 = USB_OTG_READ_REG32(&pdev->regs.HC_REGS[hc_num]->HCCHAR);   hcchar.b.oddfrm = USB_OTG_IsEvenFrame(pdev);     /* Set host channel enable */   hcchar.b.chen = 1;   hcchar.b.chdis = 0;   USB_OTG_WRITE_REG32(&pdev->regs.HC_REGS[hc_num]->HCCHAR, hcchar.d32);     if (!pdev->host.hc[hc_num].ep_is_in && pdev->host.hc[hc_num].xfer_len > 0)   {     switch(pdev->host.hc[hc_num].ep_type)     {       /* Non periodic transfer */     case EP_TYPE_CTRL:     case EP_TYPE_BULK:       hnptxsts.d32 = USB_OTG_READ_REG32(&pdev->regs.GREGS->GNPTXSTS);       len_words = (pdev->host.hc[hc_num].max_packet + 3) / 4;             /* check if at least 1 MPS FIFO space available */       if(len_words > hnptxsts.b.nptxfspcavail)       {         /* need to process data in nptxfempty interrupt */         intmsk.b.nptxfempty = 1;         USB_OTG_MODIFY_REG32( &pdev->regs.GREGS->GINTMSK, 0, intmsk.d32);        }       else       {         /*write packet into the Tx FIFO. */         USB_OTG_WritePacket(pdev,                             pdev->host.hc[hc_num].xfer_buff ,                             hc_num, pdev->host.hc[hc_num].xfer_len);   

//if xfer_len> hnptxsts.b.nptxfspcavail, then fifo space isn't enough

      }             break;       /* Periodic transfer */     case EP_TYPE_INTR:     case EP_TYPE_ISOC:       hptxsts.d32 = USB_OTG_READ_REG32(&pdev->regs.HREGS->HPTXSTS);       len_words = (pdev->host.hc[hc_num].max_packet + 3) / 4;       /* check if at least 1 MPS FIFO space available */       if(len_words > hptxsts.b.ptxfspcavail)       {         /* need to process data in ptxfempty interrupt */         intmsk.b.ptxfempty = 1;         USB_OTG_MODIFY_REG32( &pdev->regs.GREGS->GINTMSK, 0, intmsk.d32);        }       else       {                 /* Write packet into the Tx FIFO. */         USB_OTG_WritePacket(pdev,                             pdev->host.hc[hc_num].xfer_buff ,                             hc_num, pdev->host.hc[hc_num].xfer_len);       }       break;           default:       break;     }       }   return status; }