Are there any temperature sensors which can be interfaced with PLDs without having to implement a SPI/I2C bus at the PLD end. I am looking for something which can be interfaced without having to be involved in the complications of code the receiver part of some protocol.
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\$\begingroup\$ There are lots of things that could be done, but they all depend on what you wantr to do with the signal, and how much range, resolution, and accuracy is actually needed. More description of your problem is needed \$\endgroup\$– Henry CrunCommented May 3, 2018 at 20:25
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\$\begingroup\$ Silego make pld with ADC/comparators, VRef in, which can read an analog sensor \$\endgroup\$– Henry CrunCommented May 3, 2018 at 20:26
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There are PWM output temperature sensors. However, this requires you to implement logic to count the ratio between the high and low time of the pulse and convert that into a temperature. This requires an oscillator, counters, etc.
The logic to convert PWM back to a temperature would probably be less complicated than an I2C interface, but perhaps more complicated than a simple SPI interface.
The MAX6577 converts the temperature into a pulse frequency. With a crystal oscillator that is much faster than the frequency period, you could count the number of clock periods in the temperature period and convert that without a ton of logic. I think the MAX6577 would be your best bet.
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\$\begingroup\$ OK. So as I understand SPI would be the simplest to implement. Can you pls. point me to a basic VHDL code to read the output of a SPI based temperature sensor. Also, it would be nice of you to point me to a simple SPI output temperature sensor. \$\endgroup\$ Commented May 5, 2018 at 7:15
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\$\begingroup\$ I actually think the max6577 frequency output sensor would be easiest to read. See the last paragraph in my answer. \$\endgroup\$– crj11Commented May 5, 2018 at 12:31
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\$\begingroup\$ Yes. But MAX6577 are expensive to SPI temperature sensors :D \$\endgroup\$ Commented May 8, 2018 at 16:23