Spectrum Brands MC.31XX - Manual (Page 51)

Standard acquisition modes Programming
(c) Spectrum GmbH 51
If the fast 8 bit mode is used the upper byte of the memory word is used to store one channel and the lower byte is used to store another
channel. Data must be read out in the normal way from channel 0 (containing 8 bit data of ch0+ch1), channel 1 (ch2+ch3), channel 4
(ch4+ch5) and channel 5 (ch6+ch7) as described above and split into the two 8 bit channels in software afterwards.
Reading out the data with SpcGetData
The function SpcGetData enables you to read out the data that is stored in the on-board memory during any of the standard recording modes
easily after the acquisition has finished. Depending on your operating system, the function is called with a different amount of parameters.
Please refer to the relating chapter earlier in this manual. The examples in this section are written in Visual C++ for Windows, so the examples
differ a little bit for the use with linux.
As the data is read out individually for every memory channel, it is important to know where the data has been stored. Please refer to the
data organization section, to get the information you need first.
Assuming that you know the memory channel or channels that contain the acquired data, you now have to decide whether you want to read
out the whole memory or just one part of it. To select the area to be read out two values are needed by the function SpcGetData.
The value ’start’ as a 32 bit integer value
This value defines the start of the memory area to be read out in samples. This result is, that you do not need to care for the number of bytes
a single sample contains. If you want to read out the whole memory this value must be set to 0.
The value ’len’ as a 32 bit integer value
This value defines the number of samples that are read out, beginning with the first sample defined by the ’start’ value mentioned above. If
you want to read out the whole on-board memory you need to program the „len“ parameter to the before programmed memory size. At this
point please keep in mind that depending on the activated channels there may be more than one board channel in one memory channel.
This „len“ value must be a total memsize for all channels that are acquired in that memory channel. As a result that means if acquiring two
channels to memory channel 0 the „len“ value must be set to „2 * memsize“.
Multiplexed data
Depending on the activated channels and the board type several channels could be stored in one memory channel. As a result that means
that „start“ and „len“ parameter have to be multiplied by the number of channels per memory channel (module). If for example two channels
have been acquired into one memory channel a call like:
reads out data of both channels from memory channel 0 starting at sample position 4k and a length of 2k. The Data array must be of course
large enough to hold data of both channels (in that case 2 * 2k = 4k of data).
Standard mode
Reading out the data is really easy, if a recording modes is used that stores non multiplexed data in the dedicated memory channels. The
next example shows, how to read out the data after having recorded two channels that have been written without multiplexing to both memory
channels.
Bit Standard Mode with
overrange bit disabled Standard Mode with
overrange bit enabled Fast 8 bit mode enabled
D15 ADx Bit 11 Overrange AD1/AD3/AD5/AD7 Bit 11 (MSB)
D14 ADx Bit 11 ADx Bit 11 AD1/AD3/AD5/AD7 Bit 10
D13 ADx Bit 11 ADx Bit 11 AD1/AD3/AD5/AD7 Bit 9
D12 ADx Bit 11 ADx Bit 11 AD1/AD3/AD5/AD7 Bit 8
D11 ADx Bit 11(MSB) ADx Bit 11(MSB) AD1/AD3/AD5/AD7 Bit 7
D10 ADx Bit 10 ADx Bit 10 AD1/AD3/AD5/AD7 Bit 6
D9 ADx Bit 9 ADx Bit 9 AD1/AD3/AD5/AD7 Bit 5
D8 ADx Bit 8 ADx Bit 8 AD1/AD3/AD5/AD7 Bit 4 (LSB)
D7 ADx Bit 7 ADx Bit 7 AD0/AD2/AD4/AD6 Bit 11(MSB)
D6 ADx Bit 6 ADx Bit 6 AD0/AD2/AD4/AD6 Bit 10
D5 ADx Bit 5 ADx Bit 5 AD0/AD2/AD4/AD6 Bit 9
D4 ADx Bit 4 ADx Bit 4 AD0/AD2/AD4/AD6 Bit 8
D3 ADx Bit 3 ADx Bit 3 AD0/AD2/AD4/AD6 Bit 7
D2 ADx Bit 2 ADx Bit 2 AD0/AD2/AD4/AD6 Bit 6
D1 ADx Bit 1 ADx Bit 1 AD0/AD2/AD4/AD6 Bit 5
D0 ADx Bit 0 (LSB) ADx Bit 0 (LSB) AD0/AD2/AD4/AD6 Bit 4 (LSB)
SpcGetData (hDrv, 0, 2 * 4096, 2 * 2048, Data);