Data logging is an important process for evaluating the functionality and performance of many electronic systems such as internet of things (IoT). Most of the mixed-signal systems digitize the signals from the sensors to generate input signals and then perform some digital signal processing on these input signals to generate output signals. Data logging of these input and output signals helps to evaluate the performance of the systems. Many of these systems contain an FPGA for digital signal processing. The FPGA can also be used to facilitate data logging. This paper presents a data logging and data extraction system which is a high capacity, low cost and ensures data integrity over gigabytes of the data. The system has been evaluated by logging data in a system, having four inputs and one output signal each having a sampling rate of 1 kHz, for five hours. Data integrity has been observed for each sample of the data. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.