As IoT devices are becoming more and more common, it has become necessary to develop new Low Power Wide Area (LPWA) technology to support massive IoT devices. In our previous work, Asynchronous Pulse Code Multiple Access (APCMA) has been proposed as a pulse-based power-saving communication protocol. In this paper, we propose a low-power and interference-resistant communication method by using Chirp Spread Spectrum (CSS) modulation for APCMA. CSS-based APCMA can communicate with a wider coverage than APCMA that is based conventional On-Off Keying of Continuous Waves (CW). We have implemented the proposed protocol using Software-Defined Radio (SDR) and confirmed that communication is possible. Comparing with LoRa, we found that the proposed communication method has less packet loss under a high duty cycle.