Serial ADC ProjectThis is a companion project to the serial DAC project. Instead of using a serial link to output an analog signal, this allows EMC to measure an analog signal, for such things such as motor current, temperatures, etc. The ADC used here is a Linear Technologies LTC1286 single channel 12 bit converter. This system could be modified to run other ADC's with additional features, such as more channels. Latest Files
This screen shot (below, click on it for a larger version) shows the I/O traces for the LTC1286 component. The top trace, in red, is the chip select output, which brings the ADC out of low power sleep mode on the falling edge. The next trace down, in blue, is the clock output. It tells the ADC to put the data bit on the data line on the falling edge. The component then reads the data line on the rising edge. The middle, green, trace is the data after it has been read. It took me a while to get used to the fact that the input, actually on the line, is like this trace but is shifted to the left about a half a clock cycle. The bottom trace, in white, is what it's all about, data ready to be used by EMC. It will need to be scaled to mean anything to humans. For instance here, I am measuring a 0 to 5 Volt signal. The ADC's output is from 0 to 4095, so to get a value for the voltage, multiply the ADC output by 5 and divide by 4095 (or ADC x .00122 = V). In this configuration, a conversion is done every 32ms or about 31 times a second. The LTC1286 itself is rated at 12.5 ksps (about 400 times faster).
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