Thesis - Department of Electronic & Computer Engineering

transmitter chip onto a receiver with the same dimension, as shown in Fig. 3.2 by theblock diagram.Every event is sent onto the bus preserving the timing information by avoiding allsorts of handshaking and buffering. To detect collisions, the bus performs the bitwisewired OR operation on the colliding codes. In their implementations, the addresses arecoded with the same numberkof “ones” such that a collision, by bitwise ORing twoor more codes, results in a code with at leastk + 1“ones”. For example, if we choosek = 2, suppose the pulse from neuron A coded by “1010”, pulse from neuron Bcoded by “0011”, by bitwise ORing operation on the two codes when there is collisionbetween them, it results in a code “1011”, which has 3 “ones”, rather than 2. This codeis not valid and is automatically ignored by the decoder, which results in the loss of thecolliding pulses.Activity-to-frequency conversionPulse accummulationEncoderbusDecoderConverter’s outputReconstructed outputTransmitter chipReceiver chipBusAddress codecollision between1010 0011 1011andFig. 3.2 The non-arbitered communication system20