**2.3 Embedded system**

Three of PC104 type PCM3353 SBCs (Single Board Computers) are chosen as core modules, each of vision, navigation, and control. PCM3353 SBC provides 4 RS232 channels plus 4 USB channels. And using these USB channels, we can easily extend the necessary serial channels (RS232/422/485) using proper USB to serial converters. PCM3718HG analogue and digital I/O board is used for various peripheral interface. In addition, two peripheral boards, including DC/DC converter system, magnetic switch circuit, leakage detection circuit, are also designed. Fig. 3 shows the inner view of electronic pressure hull.

Fig. 3. Electronics system of P-SURO AUV.
