Spectrum M2p.59 Series, Hardware Manual, Page: 125 / 190

Multi Purpose I/O Lines On-board I/O lines (X0, X1, X2, X3)
(c) Spectrum Instrumentation GmbH 125
Synchronous digital inputs
The cards of the M2p series allow a very detailed setup on how to optionally record synchronous digital channels along with analog acqui -
sition. The SPC_DIGMODEx register allows the setup separately for every analog channel. The table below shows the related registers and
the values that correspond with the different possibilities. The mask and mode and mode values have to properly be combined. This is shown
in the example below the tables:
Each mask constant has to be bitwise AND combined with a source/mode constant, to define which digital source will be inserted at which
position of the analog sample. The SPC_DIGMODEx register defines then, what analog channel this is applied to.
The driver will automatically scale the analog samples prior to inserting the digital channels to keep the channel at the maximum possible
resolution.
Sample Format
Any channels that will not store any digital inputs within their samples still provide the full 16 bit resolution. :
* 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.
Table 73: Spectrum API: digital input options registers
Register Value Direction Description
SPC_DIGMODE0 47250 read/write Set the digital input sources for channel 0.
SPC_DIGMODE1 47251 read/write Set the digital input sources for channel 1.
SPC_DIGMODE2 47252 read/write Set the digital input sources for channel 2.
SPC_DIGMODE3 47253 read/write Set the digital input sources for channel 3.
SPC_DIGMODE4 47254 read/write Set the digital input sources for channel 4.
SPC_DIGMODE5 47255 read/write Set the digital input sources for channel 5.
SPC_DIGMODE6 47256 read/write Set the digital input sources for channel 6.
SPC_DIGMODE7 47257 read/write Set the digital input sources for channel 7.
SPCM_DIGMODE_OFF 00000000h Disable acquisition of digital data for the masked analog bit (see masks below).
SPCM_DIGMODE_X1 294A5000h Enable acquisition of multi-purpose input X1 for the masked analog bit (see masks below).
SPCM_DIGMODE_X2 318C6000h Enable acquisition of multi-purpose input X2 for the masked analog bit (see masks below).
SPCM_DIGMODE_X3 39CE7000h Enable acquisition of multi-purpose input X3 for the masked analog bit (see masks below).
DIGMODEMASK_BIT15 F8000000h Enable acquisition of a digital source (sources see above) into bit15 of the analog sample.
DIGMODEMASK_BIT14 07C00000h Enable acquisition of a digital source (sources see above) into bit14 of the analog sample.
DIGMODEMASK_BIT13 003E0000h Enable acquisition of a digital source (sources see above) into bit13 of the analog sample.
Table 74: Spectrum API: data organization for different digital input option configurations
Standard Mode 1 digital input enabled 2 digital inputs enabled 3 digital inputs enabled
Data bit 16 bit
ADC resolution
15 bit
ADC resolution
14 bit
ADC resolution
13 bit
ADC resolution
D15 ADx Bit 15 (MSB) Digital bit 0 (any X input)* Digital bit 0 (any X input)* Digital bit 0 (any X input)*
D14 ADx Bit 14 ADx Bit 15 (MSB) Digital bit 1 (any X input)* Digital bit 1 (any X input)*
D13 ADx Bit 13 ADx Bit 14 ADx Bit 15 (MSB) Digital bit 2 (any X input)*
D12 ADx Bit 12 ADx Bit 13 ADx Bit 14 ADx Bit 15 (MSB)
D11 ADx Bit 11 ADx Bit 12 ADx Bit 13 ADx Bit 14
D10 ADx Bit 10 ADx Bit 11 ADx Bit 12 ADx Bit 13
D9 ADx Bit 9 ADx Bit 10 ADx Bit 11 ADx Bit 12
D8 ADx Bit 8 ADx Bit 9 ADx Bit 10 ADx Bit 11
D7 ADx Bit 7 ADx Bit 8 ADx Bit 9 ADx Bit 10
D6 ADx Bit 6 ADx Bit 7 ADx Bit 8 ADx Bit 9
D5 ADx Bit 5 ADx Bit 6 ADx Bit 7 ADx Bit 8
D4 ADx Bit 4 ADx Bit 5 ADx Bit 6 ADx Bit 7
D3 ADx Bit 3 ADx Bit 4 ADx Bit 5 ADx Bit 6
D2 ADx Bit 2 ADx Bit 3 ADx Bit 4 ADx Bit 5
D1 ADx Bit 1 ADx Bit 2 ADx Bit 3 ADx Bit 4
D0 ADx Bit 0 (LSB) ADx Bit 1 (LSB) ADx Bit 2 (LSB) ADx Bit 3 (LSB)