source: buchla-68k/ram/puteq.c@ 8c8b4e5

/*
   =============================================================================
        puteq.c -- output functions for the LMC835 EQ chip on the Buchla 700
        Version 3 -- 1987-12-10 -- D.N. Lynx Crowe
   =============================================================================
*/

#define TESTER          0

#if     TESTER
#define MAXLINE         4
#endif

#include "ram.h"

#define EQ_STB          0x04
#define EQ_DAT          0x08
#define EQ_CLK          0x10

#define EQ_IDL          (EQ_STB | EQ_CLK)
#define EQ_MASK         (EQ_STB | EQ_CLK | EQ_DAT)

#define EQ_A6DB         0x20
#define EQ_B6DB         0x10

#define EQ_6DB          (EQ_A6DB | EQ_B6DB)

#define EQ_ADD          0x40

#define PSG_ADDR        0
#define PSG_READ        0
#define PSG_WRIT        2

#define PSG_IOEN        7
#define PSG_IDLE        0xBF

#define PSG_PRTB        15

#if     TESTER
char    cmdline[32];
#endif

int8_t eqgaint[] = {

        0x00,   /*  0 db */
        0x20,   /*  1 db */
        0x10,   /*  2 db */
        0x08,   /*  3 db */
        0x04,   /*  4 db */
        0x02,   /*  5 db */
        0x12,   /*  6 db */
        0x2A,   /*  7 db */
        0x16,   /*  8 db */
        0x01,   /*  9 db */
        0x29,   /* 10 db */
        0x2D,   /* 11 db */
        0x2F    /* 12 db */
};

void puteq(int8_t byte)
{
        int16_t i;
        volatile uint8_t *psg;
        int8_t eqdata;

        psg = &io_tone;

        *(psg + PSG_ADDR) = PSG_IOEN;           /* setup PSG I/O controls */
        *(psg + PSG_WRIT) = PSG_IDLE;

        *(psg + PSG_ADDR) = PSG_PRTB;           /* setup EQ control lines */
        eqdata = EQ_IDL | (*(psg + PSG_READ) & ~EQ_MASK);

        for (i = 0; i < 8; i++) {               /* send out 8 bits */

                if (byte & 1)                   /* setup data line from LSB */
                        eqdata |= EQ_DAT;       /* "1" */
                else
                        eqdata &= ~EQ_DAT;      /* "0" */

                eqdata &= ~EQ_CLK;              /* set clock low */

                *(psg + PSG_ADDR) = PSG_PRTB;
                *(psg + PSG_WRIT) = eqdata;

                eqdata |= EQ_CLK;               /* set clock high */

                *(psg + PSG_ADDR) = PSG_PRTB;
                *(psg + PSG_WRIT) = eqdata;

                byte >>= 1;                     /* shift next bit into LSB */
        }

        eqdata &= ~EQ_STB;                      /* set strobe low */

        *(psg + PSG_ADDR) = PSG_PRTB;
        *(psg + PSG_WRIT) = eqdata;

        eqdata |= EQ_STB;                       /* set strobe high */

        *(psg + PSG_ADDR) = PSG_PRTB;
        *(psg + PSG_WRIT) = eqdata;
}

void sendeq(int8_t band, int8_t gain)
{
        puteq(band);
        puteq(gain);
}

int8_t gain2eq(int16_t gain)
{
        register int8_t eqdat;

        if (gain > 0)
                eqdat = eqgaint[gain] | EQ_ADD;
        else
                eqdat = eqgaint[-gain];

        return(eqdat);
}

#if     TESTER

char    ahex[] = "0123456789abcdefABCDEF";

/*
   ============================================================================
        xdtoi -- convert hex ASCII to an int digit
   ============================================================================
*/

int
xdtoi(c)
register int c;
{
        register int i;
        register char *ap = &ahex[0];

        for (i = 0; i < 22; i++)
                if (c EQ *ap++)
                        if (i >15)
                                return(i - 6);
                        else
                                return(i);

        return(-1);
}

main()
{
        short   rc, c, j;
        register long   temp;
        char    gain, band;
        register char   *aptr;

        printf("\n\nBuchla 700 EQ chip test -- Enter data in hex\n\n");

        do {

                printf("Band = ");

                rc = getln(CON_DEV, MAXLINE, cmdline);

                if (rc EQ A_CR) {

                        printf("\n");

                        temp = 0L;
                        aptr = cmdline;

                        if (A_CR EQ (*aptr & 0x00FF)) {

                                xtrap15();
                                continue;
                        }

                        if (CTL('G') EQ (*aptr & 0x00FF)) {

                                while (0 EQ BIOS(B_RDAV, CON_DEV))
                                        sendeq(band, gain);

                                BIOS(B_GETC, CON_DEV);
                                continue;
                        }

                        while (isxdigit(c = *aptr++))
                                temp = (temp << 4) + xdtoi(c);

                        if (temp > 255) {

                                printf("\nInput must be < 100\n\n");
                                continue;
                        }

                        band = (char)(temp & 0x000000FFL);

                } else {

                        printf("Huh ?\n\n");
                        continue;
                }

                printf("Gain = ");

                rc = getln(CON_DEV, MAXLINE, cmdline);

                if (rc EQ A_CR) {

                        printf("\n");

                        temp = 0L;
                        aptr = cmdline;

                        if (A_CR EQ (*aptr  & 0x00FF)) {

                                xtrap15();
                                continue;
                        }

                        while (isxdigit(c = *aptr++))
                                temp = (temp << 4) + xdtoi(c);

                        if (temp > 255) {

                                printf("\nInput must be < 100\n\n");
                                continue;
                        }

                        gain = (char)(temp & 0x000000FFL);

                } else {

                        printf("Huh ?\n\n");
                        continue;
                }

                sendeq(band, gain);
                printf("\n");

        } while (1);
}

#endif