We present a new system for functional electrical stimulation (FES) applications based on networked stimulation units. They embed an advanced analog circuit, which provides multipolar and multiphasic stimulation profiles, and digital circuits, which ensure safety, locally executed programmed profiles, and communication with the master controller. This architecture is thus based on distributed stimulation units (DSU) that need only a two-wire bus to communicate, regardless of the number of poles of each DSU-driven electrode. This structure minimizes the required bandwidth between master and distributed units, increases the safety and stimulation features and decreases the complexity of the surgical approach. We have successfully tested this network-based stimulation architecture on benchtop stimulators. This original approach allows broad exploration of all possible methods to stimulate peripheral nerves, particularly in the goal of restoring the motor function. It provides a powerful research device to determine the optimal, least aggressive and the most efficient way to activate the peripheral nervous system using an implanted FES system that is less invasive than other existing devices.

This paper deals with the automatic translation of interpreted generalized Petri Nets with time into VHDL, for rapid prototyping on programmable logic device purposes. This approach is based on the component orientation of the VHDL language, and defines two elementary VHDL components: the place and the transition. This transition component is a "pivot" element of the approach, since it supports all the interconnections between places and transitions (i.e. it allows the structure of the PN to be built). Moreover, with the aim to reduce power consumption, we proposed to control the VHDL component's activity according to an approach based on the "activity propagation" principle since PNs are oriented graphs.

In the context of distributed systems, the communication requirements are very different depending on the supported application, the system topology and the environment. The functional electrical stimulation is a critical and real time application domain: communications have to be safe (no loss, neither long nor unexpected delay). Therefore, an important part of this system from an efficiency point of view is the medium access mechanism. To fit with the specific constraints of our context, a new MAC protocol has been designed: STIMAP (Sliding Time Interval based Medium Access Protocol). This article presents a formal validation of this new protocol, allowing the validation of its behavior in an exhaustive way.