This demo provides an example on how to use the communication interface provided in the modules firmware,
to setup the pre-amplification and trigger an ADC measurement.
The module saves after a trigger event 1 million samples of ADC measurement in its SDRAM.
Those values are gathered in parts of 16 kbytes and converted from RAW ADC data to standard integers and
floating point numbers.
The signal is plotted, showing its value over time, and Fourier transformed, showing its frequency spectrum.
The user can easily access the pre-amplification and the length of the processed and plotted part of the data
through a GUI.
To communicate with the module, a serial comport port with a speed set to 115200 bits needs to be opened.
Commands consists of a single character in UTF-8 encoding.
It is good practice to communication with the module following these steps:
These steps apply also for read operations.
The module provides a method to gather highly accurate consecutive ADC measurements in a single event.
In this mode of operation, one mega sample of ADC values are performed and stored inside the modules
SD-RAM.
The following step should be taken in this mode:
After a trigger event, the one mega sample of data is stored until your retrigger. So processing the data can
be done for each chunk individually or the whole one mega sample.
Information to convert the RAW ADC data into standard integer values.
Resolution: 18-bit / 5 nibbles
Maximum sampling rate: 2 MSPS
Order of Values:
Hex | Dec | Hex | Dec | ||
---|---|---|---|---|---|
Mid scale | 0x00000 | 0 | |||
Positive 1 LSB | 0x00001 | 1 | to full scale -1 LSB | 0x1ffff | 131071 |
Negative full scale | 0x20000 | 131072 | to -1 LSB | 0x3FFFF | 262143 |
The layout of the ADC circuit is further described in the Analog Devices circuit note CN-0385.
Resolution: 16-bit / 4 nibbles
Maximum sampling rate: 0.5 MSps / 1 MSps
Order of Values:
Hex | Dec | Hex | Dec | ||
---|---|---|---|---|---|
Negative full scale is | 0x0000 | 0 | to -1 LSB | 0x7fff | 32767 |
Mid scale is | 0x8000 | 32768 | |||
Positive 1 LSB | 0x8001 | 32769 | to full scale | 0xffff | 65536 |
The layout of the ADC circuit is further described in the Analog Devices circuit note CN-0393.