Table 78: Sample Format Of Analog Samples In Combination With Digital Input Channels - Spectrum M2p.59 Series Hardware Manual

Additional I/O lines with Option -DigSMB and -DigFX2
Sample format (with more than 3 digital channels)
In combination with the additional digital I/O lines offered by the -DigSMB or -DigFX2 any additional reduction of the ADC resolution is
possible, including the complete replacement of the analog data:

Table 78: Sample format of analog samples in combination with digital input channels

Standard Mode 4 digital inputs enabled
Data bit 16 bit 12 bit
ADC resolution ADC resolution
D15 ADx Bit 15 (MSB) Digital bit 0 (any X input)*
D14 ADx Bit 14 Digital bit 1 (any X input)*
D13 ADx Bit 13 Digital bit 2 (any X input)*
D12 ADx Bit 12 Digital bit 3 (any X input)*
D11 ADx Bit 11 ADx Bit 15 (MSB)
D10 ADx Bit 10 ADx Bit 14
D9 ADx Bit 9 ADx Bit 13
D8 ADx Bit 8 ADx Bit 12
D7 ADx Bit 7 ADx Bit 11
D6 ADx Bit 6 ADx Bit 10
D5 ADx Bit 5 ADx Bit 9
D4 ADx Bit 4 ADx Bit 8
D3 ADx Bit 3 ADx Bit 7
D2 ADx Bit 2 ADx Bit 6
D1 ADx Bit 1 ADx Bit 5
D0 ADx Bit 0 (LSB) ADx Bit 4 (LSB)
* Any X-input can be used as a source for that digital channel, except X0, which is output only.
Please note that automatic sign extension of analog data is ineffective as soon as one digital input line is
activated and the software must properly mask out all the digital bits from the samples.
The digital source has to be properly set to input direction to be a valid digital source. Also the analog channel
into that the digital signals shall be routed to must be activated properly for acquisition as described in the
„Channel Selection" passage.
The following example shows how to enable all sixteen channels of the digital input option and completely replace analog channel 2:
for (int i = 0; i < 15; i++)
spcm_dwSetParam_i32 (hDrv, (SPCM_X4_MODE + i), SPCM_XMODE_DIGIN);
// Enable acquisition of X19..X4 inputs to completely replace analog samples of channel 2
spcm_dwSetParam_i32 (hDrv, SPCM_DIGMODE2, SPCM_DIGMODE_CHREPLACE);
The following example shows how to enable four digital channels provided via the multi-purpose lines X2, X3, X8 and X13 to channel 0 only
and hence reduce the resolution of this channel to 12 bit:
spcm_dwSetParam_i32 (hDrv, SPCM_X2_MODE,
spcm_dwSetParam_i32 (hDrv, SPCM_X3_MODE,
spcm_dwSetParam_i32 (hDrv, SPCM_X8_MODE,
spcm_dwSetParam_i32 (hDrv, SPCM_X13_MODE, SPCM_XMODE_DIGIN);
// define and clear a temporary variable
uint32 dwValue = 0;
// add four sources (X2, X3, X8 and X13) at four different positions (bit15, bit14, bit13 and bit12)
dwValue |= (DIGMODEMASK_BIT15 & SPCM_DIGMODE_X2);
dwValue |= (DIGMODEMASK_BIT14 & SPCM_DIGMODE_X3);
dwValue |= (DIGMODEMASK_BIT13 & SPCM_DIGMODE_X8);
dwValue |= (DIGMODEMASK_BIT12 & SPCM_DIGMODE_X13); // store X13 in Sample Bit12
// and write value to channel 0 digmode register. Resulting Ch0 A/D samples will be 12bit.
spcm_dwSetParam_i32 (hDrv, SPCM_DIGMODE0, dwValue);
130
5 digital inputs enabled
11 bit
ADC resolution
Digital bit 0 (any X input)*
Digital bit 1 (any X input)*
Digital bit 2 (any X input)*
Digital bit 3 (any X input)*
Digital bit 4 (X15)
ADx Bit 15 (MSB)
ADx Bit 14
ADx Bit 13
ADx Bit 12
ADx Bit 11
ADx Bit 10
ADx Bit 9
ADx Bit 8
ADx Bit 7
ADx Bit 6
ADx Bit 5 (LSB)
SPCM_XMODE_DIGIN); // X2
SPCM_XMODE_DIGIN); // X3
SPCM_XMODE_DIGIN); // X8
// X13 set to synchronous input
// store X2
// store X3
// store X8
(c) Spectrum Instrumentation GmbH
8 digital inputs enabled
... 8 bit
ADC resolution
... Digital bit 0 (any X input)*
... Digital bit 1 (any X input)*
... Digital bit 2 (any X input)*
... Digital bit 3 (any X input)*
... Digital bit 4 (X15)
... Digital bit 5 (X14)
... Digital bit 6 (X13)
... Digital bit 7 (X12)
... ADx Bit 15 (MSB)
... ADx Bit 14
... ADx Bit 13
... ADx Bit 12
... ADx Bit 11
... ADx Bit 10
... ADx Bit 9
... ADx Bit 8 (LSB)
// X4..X19 set to synchronous input
set to synchronous input
set to synchronous input
set to synchronous input
in Sample Bit15
in Sample Bit14
in Sample Bit13
Multi Purpose I/O Lines
16 digital inputs ena-
bled
... ADC sample completely
replaced
... Digital bit 0 (any X input)*
... Digital bit 1 (any X input)*
... Digital bit 2 (any X input)*
... Digital bit 3 (any X input)*
... Digital bit 4 (X15)
... Digital bit 5 (X14)
... Digital bit 6 (X13)
... Digital bit 7 (X12)
... Digital bit 8 (X11)
... Digital bit 9 (X10)
... Digital bit 10 (X9)
... Digital bit 11 (X8)
... Digital bit 12 (X7)
... Digital bit 13 (X6)
... Digital bit 14 (X5)
... Digital bit 15 (X4)