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Honored Contributor
Honored ContributorHelp creating a USB Device
Hello all, I have another beginner question. I've recently designed a Nios II system on the DE2 board with a custom cryptographic hashing function for use in a research application, and now I need to connect it to a PC via USB. I see that in SOPC builder, under USB, I have an evaluation licensed IP from SLS called the USB2.0HR. I added it to my system, and connected the avalon slave port to the Nios as the master. However I have several questions (probably with more to come later).
1) In the picture in the USB2.0HR documentation, I see that the avalon slave port is also connected to a DMA. I have never used a DMA, do I need one? I don't intend to do huge mass transfers on a streaming basis. I take 300 or so bytes in, process it, and send 200 or so bytes back out, and only when instructed to do so by the host PC. 2) After I generate the system in SOPC builder, I looked at the VHDL file for the system and saw these ports:
-- the_sls_avalon_usb20hr_0
signal Data_to_and_from_the_sls_avalon_usb20hr_0 : INOUT STD_LOGIC_VECTOR (7 DOWNTO 0);
signal LineState_to_the_sls_avalon_usb20hr_0 : IN STD_LOGIC_VECTOR (1 DOWNTO 0);
signal OpMode_from_the_sls_avalon_usb20hr_0 : OUT STD_LOGIC_VECTOR (1 DOWNTO 0);
signal RxActive_to_the_sls_avalon_usb20hr_0 : IN STD_LOGIC;
signal RxError_to_the_sls_avalon_usb20hr_0 : IN STD_LOGIC;
signal RxValid_to_the_sls_avalon_usb20hr_0 : IN STD_LOGIC;
signal SuspendM_from_the_sls_avalon_usb20hr_0 : OUT STD_LOGIC;
signal TermSel_from_the_sls_avalon_usb20hr_0 : OUT STD_LOGIC;
signal TxReady_to_the_sls_avalon_usb20hr_0 : IN STD_LOGIC;
signal TxValid_from_the_sls_avalon_usb20hr_0 : OUT STD_LOGIC;
signal XcvSelect_from_the_sls_avalon_usb20hr_0 : OUT STD_LOGIC;
signal usb_vbus_to_the_sls_avalon_usb20hr_0 : IN STD_LOGIC
