在用CYUSB3014做数据传输时，从FIFO读不到数据

只看该作者 · 2016-12-19 19:45

本帖最后由 Tori128 于 2016-12-19 19:47 编辑

用CYusb3014做USB3.0的数据传输，利用同步从FIFO模式，从FIFO读数据时空标志位一直是0，也就是空，读不到数据，请问大神们，这是怎么回事呢？附图

只看该作者 · 2016-12-19 19:48

这是控制代码
process(current_GPIF_STATE,usb_rd_empty,usb_wr_full)
begin
--next_GPIF_STATE <= current_GPIF_STATE;
case current_GPIF_STATE is

   when USB_RD_IDEL  =>

   next_GPIF_STATE <= USB_RD_W1;

--usb interface------------------
usb_cs_buf <= act_off_usb;
usb_wr_buf <= act_off_usb;
usb_rd_buf <= act_off_usb;
usb_oe_buf <= act_off_usb;

usb_pkt_buf <= act_off_usb;

   ----PC write cmd
   usb_a0_buf <= '0';
   usb_a1_buf <= '0';

when USB_RD_W1 =>
next_GPIF_STATE <= USB_RD_W2;
usb_a0_buf <= '1';
         usb_a1_buf <= '1';

when USB_RD_W2 =>
next_GPIF_STATE <= USB_RD_W3;
            usb_a0_buf <= '1';
         usb_a1_buf <= '1';
when USB_RD_W3 =>
next_GPIF_STATE <= USB_RD_CS;
            usb_a0_buf <= '1';
         usb_a1_buf <= '1';
when USB_RD_CS =>
next_GPIF_STATE <= USB_RD_OE;
usb_cs_buf <= act_on_usb;
usb_a0_buf <= '1';
         usb_a1_buf <= '1';
when USB_RD_OE =>
            next_GPIF_STATE <= USB_RD_START_STATE;
   usb_cs_buf <= act_on_usb;
usb_a0_buf <= '1';
         usb_a1_buf <= '1';
usb_oe_buf <= act_on_usb;

when USB_RD_START_STATE =>
   usb_cs_buf <= act_on_usb;
usb_a0_buf <= '1';
         usb_a1_buf <= '1';

usb_oe_buf <= act_on_usb;
usb_rd_buf <= act_on_usb;

if usb_rd_empty = act_off_usb then
   next_GPIF_STATE <= USB_RD_START_STATE;
            else
               next_GPIF_STATE <= USB_RD_CS;
end if;

end case;
end process;

只看该作者 · 2016-12-19 19:49

C:\Users\Administrator\Desktop

只看该作者 · 2016-12-19 19:53

这是Chipscope抓数据的结果