Programmable auto-converting analog to digital conversion module

DETAILED DESCRIPTION According to the present invention, an A/D conversion on a device is accomplished using fewer A/D conversion circuits than analog input channels.
Signals from many analog input channels are time multiplexed and provided as a single input signal to each A/D conversion circuit.
This avoids having to provide a dedicated A/D conversion circuit to each analog input channel on a device and therefore saves power and space on the device.
According to an embodiment of the present invention, a device automatically converts a plurality of analog input channels using a single analog to digital conversion circuit.
The device includes a multiplexer, an analog to digital conversion circuit and a configurable channel controller.
The multiplexer has at least two analog input channels.
The multiplexer also has control inputs and an output.
The analog to digital conversion circuit has inputs coupled to the output of the multiplexer and a clock signal.
The analog to digital conversion circuit outputs a conversion value based on a voltage associated with the output of the multiplexer in successive clock cycles.
The configurable channel controller outputs a control signal to the control inputs of the multiplexer to automatically select successive ones of the analog input channels for conveying to the analog to digital conversion circuit.
The configurable channel controller may have a configuration set based on values stored in one or more registers.
The configuration may also include enable values that selectively enable each of the analog input channels for auto-conversion based on some of the values.
In another embodiment, the configurable channel controller receives an interrupt signal to initiate outputting the control signal.
In still another embodiment, the conversion value is output in successive clock cycles to registers where each register stores the converted value corresponding to the selected analog input channel.
In still another embodiment, the device also includes comparators for comparing the converted value with a threshold value and a protocol engine for outputting a message when the converted value crosses the threshold value