Implementando el EPP de Digilent

Estoy intentando implementar la interfaz paralela de Digilent desde su SDK . Puede leer específicamente la interfaz en este manual . Estoy usando la placa Basys 2 250k.

Estoy tratando de averiguar qué estoy haciendo mal, lo que creo que es solo un problema con el tiempo en mi VHDL.

Aquí hay un diagrama de tiempo para leer datos del FPGA:

ElVHDLseparecea:

libraryIEEE;useIEEE.STD_LOGIC_1164.ALL;--Uncommentthefollowinglibrarydeclarationifusing--arithmeticfunctionswithSignedorUnsignedvalues--useIEEE.NUMERIC_STD.ALL;--Uncommentthefollowinglibrarydeclarationifinstantiating--anyXilinxprimitivesinthiscode.--libraryUNISIM;--useUNISIM.VComponents.all;entityDeppSwitchesisPort(mclk:instd_logic;EppDB:inoutstd_logic_vector(7downto0);EppAstb:instd_logic;EppDstb:instd_logic;EppWR:instd_logic;EppWait:outstd_logic;Led:outstd_logic_vector(7downto0);sw:instd_logic_vector(7downto0);btn:instd_logic_vector(4downto0);stepCurrOutDebug:outstd_logic_vector(7downto0);stepNextOutDebug:outstd_logic_vector(7downto0));endDeppSwitches;architectureBehavioralofDeppSwitchesissignalbusEppOut:std_logic_vector(7downto0);--ChanneltosendbitstopcsignalbusEppIn:std_logic_vector(7downto0);--AddressthatthepcsendstofpgasignalbusEppData:std_logic_vector(7downto0);--BitstosendtoPCsignalperipheralWait:std_logic:='0';constantstepIdle:std_logic_vector(7downto0):="0001" & "0000";
    constant stepRead: std_logic_vector(7 downto 0) := "0010" & "0000"; -- PC Read from FPGA
    constant stepRead2: std_logic_vector(7 downto 0) := "0100" & "0000"; -- PC Read from FPGA

    signal stepCurr: std_logic_vector(7 downto 0) := stepIdle;
    signal stepNext: std_logic_vector(7 downto 0);
begin
    Led <= sw;

    -- Handshake signal used to indicate when the peripheral is ready to accept data or has data available.
    EppWait <= peripheralWait;

    -- Data bus direction control. The internal input data bus always
    -- gets the port data bus. The port data bus drives the internal
    -- output data bus onto the pins when the interface says we are doing
    -- a read cycle and we are in one of the read cycles states in the
    -- state machine.
    busEppIn <= EppDB;
    EppDB <= busEppOut;

    -- Hook the data bits to the switches
    busEppData <= sw;

    -- We need this to see the state when debugging
    stepCurrOutDebug <= stepCurr;
    stepNextOutDebug <= stepNext;

    -- Advance the state machine
    process(mclk)
    begin
        if rising_edge(mclk) then
            stepCurr <= stepNext;
        end if;
    end process;

    process(mclk)
    begin
        if rising_edge(mclk) then
            case stepCurr is
                when stepIdle =>
                    peripheralWait <= '0';
                    busEppOut <= "ZZZZZZZZ";

                    if EppWR = '1' then
                        stepNext <= stepRead;
                    else
                        stepNext <= stepIdle;
                    end if;

                when stepRead =>
                    if EppDstb = '0' then
                        busEppOut <= busEppData;
                        peripheralWait <= '1';

                        stepNext <= stepRead2;
                    end if;

                when stepRead2 =>
                    if EppDstb = '1' then
                        busEppOut <= "ZZZZZZZZ";

                        stepNext <= stepIdle;
                    else 
                        stepNext <= stepRead2;
                    end if;

                when others => stepNext <= stepIdle;
            end case;
        end if;
    end process;

end Behavioral;

Después de la simulación con este banco de pruebas, obtengo estos resultados:

-- insert stimulus here 
EppWR <= '1';
EppDstb <= '1';
sw <= "00001111";

wait for 4 ns;
EppDstb <= '0';
wait for 50 ns;
EppDstb <= '1';

MiproyectodeC++secompilabienyusé Hamsters EPP Performace project como mi base (que comenzó a funcionar bien) y luego entró en el archivo de demostración de la descarga del SDK y tomó la función DoGetReg() para comenzar a leer bytes.

Cada vez que ejecuto el programa obtengo ...

Opening
Enabling
Getting
DeppGetReg failed

Aquí está el código:

// DeppSwitches.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <windows.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#include "dpcdecl.h"
#include "depp.h"
#include "dmgr.h"

static HIF hif = hifInvalid;

void ErrorExit();
void DoGetReg();

int main(int cszArg, char * rgszArg[]) 
{
    fprintf(stderr,"Opening\n");
    if(!DmgrOpen(&hif, "Basys2")) // Change to Basys2 for the other board.
    {  
        printf("DmgrOpen failed (check the device name you provided)\n");
        return 0;
    }

    fprintf(stderr,"Enabling\n");
    if(!DeppEnable(hif)) 
    {
        printf("DeppEnable failed\n");
        return 0;
    }

    fprintf(stderr,"Getting\n");
    DoGetReg();

    if( hif != hifInvalid ) 
    {
        DeppDisable(hif);
        DmgrClose(hif);
    }
    return 0;
}

void DoGetReg() 
{
    BYTE    idReg;
    BYTE    idData;

    idReg = (BYTE)0;

    // DEPP API Call: DeppGetReg
    if(!DeppGetReg(hif, idReg, &idData, fFalse)) { 
        printf("DeppGetReg failed\n");
        ErrorExit();
    }

    printf("Complete. Recieved data %d\n", idData);

    return;
}


/* ------------------------------------------------------------ */
/***    ErrorExit
**
**  Parameters:
**      none
**
**  Return Value:
**      none
**
**  Errors:
**      none
**
**  Description:
**      Disables DEPP, closes the device, close any open files, and exits the program
*/
void ErrorExit() {
    if( hif != hifInvalid ) {
        // DEPP API Call: DeppDisable
        DeppDisable(hif);

        // DMGR API Call: DmgrClose
        DmgrClose(hif);
    }

    exit(1);
}