IJITEST_20261027163055_IJITEST-2026-019 20261027163055 International Journal of Innovative Trends in Engineering Science and Technology editor@ijitest.org Felix Academic Publications International Journal of Innovative Trends in Engineering Science and Technology IJITEST 3139-6887 07 2026 1 5 VIKRAM KEERTHANA JNTUGV Miracle Educational Society Group of Institutions P SRIDEVI JNTUGV Miracle Educational Society Group of Institutions D RAJITHA JNTUGV Miracle Educational Society Group of Institutions A configurable SPI interface based on APB bus using four slaves is proposed in this thesis. The SPI interface transmission information is configured through APB bus, which can realize the master-slave mode switching, 4 kinds of clock transmission mode switching and MSB/LSB communication mode switching. Meanwhile the transmission rate can be selected and the transmission length can be variable from 1 to 32 bits. Based on the SPI transmission protocol, the proposed design uses a finite state machine method to control the transmission timing of the SPI interface. This design was verified through RTL simulation and Verilog testbench for verification. The verification results show that the functional of SPI interface is correct and the data transmission is stable. 07 30 2026 8 11 https://creativecommons.org/licenses/by/4.0/ 10.5281/zenodo.22131568 https://ijitest.org/article/ijitest-2026-019 https://ijitest.org/api/files/published/IJITEST-2026-019-published.pdf https://ijitest.org/api/files/published/IJITEST-2026-019-published.pdf