#define STX104_INTRA_SAMPLE_TIMING           5000  /* nanoseconds */
#define STX104_TIME_RESOLUTION               25    /* nanoseconds */

/*##################################################################################
*                                                      ANALOG INPUT TIMING FUNCTIONS
*/

/*****************************************************************
/                               ANALOG INPUT MINIMUM SETTLING TIME
*/
static unsigned long STX104_AI_Time_Settling_Minimum( float ai_capacitance_pf, float ai_resistance_ohms )
{
    unsigned long settle_time_ns;

    //settle_time = ai_resistance_ohms * ai_capacitance_pf * pow10(-12) * 16 * ln(2) * pow10(9)
    settle_time_ns = (unsigned long) ( ai_resistance_ohms * ai_capacitance_pf * pow10(-3) * 16 * log(2) );

    return( settle_time_ns );
}
/*****************************************************************
/                                         ANALOG INPUT 8254 TIMING
*/
static void STX104_AI_Timing_8254_Set( int board, long time_interval_ns )
{
    long high_count;
    long low_count;
    unsigned int octet;

    STX104_Set_Bank( board, 0 );

    /* assumes 10MHz clock (i.e. no 1MHz jumper) */
    low_count  = 10L; /* 1 microsecond intervals */

    high_count = time_interval_ns / 1000;
    while ( high_count > 65536L )
    {
        high_count = high_count >> 1;
        low_count  = low_count << 1;
    }
    while ( high_count < 2L )
    {
        high_count = high_count << 1;
        low_count  = low_count >> 1;
    }
    /* set counter/timer 2  */
    outportb( stx104_base_address[board] + STX104_CT_CONFIGURATION, 0xB4 );
    octet = ((unsigned int) high_count) & 0x00FF;
    outp( stx104_base_address[board] + STX104_CT2_DATA, octet );
    octet = ((unsigned int) high_count) >> 8;
    outp( stx104_base_address[board] + STX104_CT2_DATA, octet );
    /* set counter/timer 1  */
    outportb( stx104_base_address[board] + STX104_CT_CONFIGURATION, 0x74 );
    octet = ((unsigned int) low_count) & 0x00FF;
    outp( stx104_base_address[board] + STX104_CT1_DATA, octet );
    octet = ((unsigned int) low_count) >> 8;
    outp( stx104_base_address[board] + STX104_CT1_DATA, octet );
}

/*****************************************************************
/                                      ANALOG INPUT GENERAL TIMING
*/
static void STX104_AI_Timing_Set( int board, unsigned long ai_time_frame_ns, unsigned long ai_time_intra_sample_ns )
{
    unsigned int adc_burst_channel_count;

    switch ( stx104_revision[board] )
    {
        case STX104_REVISION_080214:
            STX104_Set_Bank( board, 1 );
            STX104_Write_Indexed_Data_Byte( board, STX104_BURST_FUNCTION_ENABLE_INDEXED, 0x40 );
            STX104_Write_Indexed_Data_Byte( board, STX104_BURST_MODE_ENABLE_INDEXED,     0x40 );
            STX104_Write_Indexed_Data_Byte( board, STX104_CONVERSION_DISABLE_INDEXED,    0x00 );
            adc_burst_channel_count = (unsigned char)( 0x0F & ( stx104_ai_channel_last[board] - stx104_ai_channel_first[board] ) );
            adc_burst_channel_count = adc_burst_channel_count << 4;
            outp( stx104_base_address[board] + STX104_PACER_CLOCK_CONTROL, adc_burst_channel_count );
            /* the following registers require the number of 25nSec intervals to achieve the selected timing */
            STX104_Write_Indexed_Data_Dword( board, STX104_ANALOG_INPUT_FRAME_TIMER, ( ai_time_frame_ns/STX104_TIME_RESOLUTION ) );
            STX104_Write_Indexed_Data_Dword( board, STX104_ANALOG_INPUT_BURST_TIMER, ( (ai_time_intra_sample_ns - STX104_INTRA_SAMPLE_TIMING) / STX104_TIME_RESOLUTION ) );
            break;
        default:
            if ( ai_time_intra_sample_ns > STX104_INTRA_SAMPLE_TIMING /*nS*/ )
            { /* cannot use adc-burst mode */
                STX104_AI_Timing_8254_Set( board, ai_time_intra_sample_ns );
                outp( stx104_base_address[board] + STX104_BURST_FUNCTION,         0x00 );
                outp( stx104_base_address[board] + STX104_BURST_MODE_ENABLE,      0x00 );
                outp( stx104_base_address[board] + STX104_CONVERSION_DISABLE,     0x00 );
            }
            else
            { /* utilize adc-burst mode */
                STX104_AI_Timing_8254_Set( board, ai_time_frame_ns );
                outp( stx104_base_address[board] + STX104_BURST_FUNCTION,         0x40 );
                outp( stx104_base_address[board] + STX104_BURST_MODE_ENABLE,      0x40 );
                outp( stx104_base_address[board] + STX104_CONVERSION_DISABLE,     0x00 );
                adc_burst_channel_count = (unsigned char)( 0x0F & ( stx104_ai_channel_last[board] - stx104_ai_channel_first[board] ) );
                adc_burst_channel_count = adc_burst_channel_count << 4;
                outp( stx104_base_address[board] + STX104_PACER_CLOCK_CONTROL, adc_burst_channel_count );
           }
    }
}