1. A method, comprising: configuring a voice trigger circuit to: receive a training sequence and store a representation of the training sequence in a training buffer in reverse of order received; detect receipt of an audio signal that is sampled into blocks; determine a plurality of energy values of the sampled audio signal blocks; perform energy binning of the plurality of energy values to determine whether speech is present in the sampled audio signal blocks; determine that speech is present in the sampled audio signal blocks received; store a representation of the sampled audio signal block in a trigger buffer; match the representation of the sampled audio signal blocks stored in the trigger buffer starting with the representation of most recently received sampled audio signal block and proceeding to oldest received sampled audio signal block, to the representation of the training sequence stored in the training buffer starting with the most recently received and proceeding to oldest received; and enable a wake up pin in the voice trigger circuit upon matching the representation to the training sequence.