ZTA-Q: an Open-source RISC-V Platform for Accurate Quantized CNN Inference

By Yike Li ^∗, Ajay Kumar M ^∗, Vishnu PS ^∗, Dimitrios S. Nikolopoulos ^‡, Bo Ji ^‡, Hans Vandierendonck ^§, Deepu John ^∗
∗ University College Dublin, Ireland 
^‡ Virginia Tech, USA 
^§ Queen’s University Belfast, UK

Abstract

Low-precision inference is widely adopted in edge AI to reduce computational cost and memory footprint. However, existing open-source accelerator platforms provide limited end-to-end support for CNNs following the standard TensorFlow Lite integer inference scheme. This paper presents ZTA-Q, an open-source RISC-V-based platform that enables accurate deployment of TensorFlow Lite INT8 models. In addition to extending operator support, ZTA-Q provides a configurable post-processing datapath for studying how circuit-level approximations, including reduced multiplier precision, shared shift scaling, and simplified rounding, affect model accuracy. The proposed system is implemented on a Digilent Arty A7-100T FPGA and operates at 83.3 MHz. Evaluations on representative CNN models show that with LUT, register, and DSP overheads of 26.3%, 12.6%, and 150%, respectively, ZTA-Q limits the degradation in both top-1 and top-5 accuracy to within 0.25 percentage points.

Index Terms—Deep Learning, Hardware accelerators, RISC-V, Quantization, FPGA

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