Linux Kernel Driver for External Analog-to-Digital and Digital-to-Analog Converters

P. Skrzypiec, Z. Marszałek (AGH Univ. of Science and Techn., Poland)

The paper presents the Linux kernel driver for analog-to-digital and digital-to-analog converters control. The proposed module is the main part of the distributed embedded system for impedance measuring applications. The designed prototype consists of three hardware components: Raspberry Pi 3, microcontroller and personal computer. Two experiments verified the functionality and parameters of the constructed system. The first one confirmed that the driver does not utilize processor time while the data processing application is not running. It also showed that the module consumes only 0.7 % and 3.3 % of two cores of a quad-core processor for data readout and its copying to the user space. The mentioned test was performed with the sampling frequency equal to 256 kHz. The second experiment determined the accuracy of impedance measurements done by the constructed prototype. Results were compared with ones realized with the commercially available measuring device usage. The determined measurements uncertainty did not exceed 1.5 %.