Quote:
Originally Posted by NiHaoMike
The hardware for it is very simple. RS232/RS485 is just bringing the UART to a common 9 pin connector via a level shifter and is useful for far more than just VFDs.
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I had already put the RS485 option on the 'wish list' on post #2
Quote:
Originally Posted by NiHaoMike
PWM is just bringing a PWM pin to a screw terminal... with some sort of buffer circuit in between. Then add an active low pass filter (literally just a resistor, capacitor, and opamp) and you also have analog output. A little more circuitry and it will also do 4-20mA output.
We can put in the hardware first and worry about the software later. We can also add WiFi capability with a CC3000 module. You can simply leave the spot blank if you're not going to use it. It's common practice in hardware engineering to provision in as many features as the space and time allow. Also use the highest end processor that is compatible with the footprint during development, then downgrade for going into production. (For a one off, just keep the high end processor as its cost - a few dollars - is practically nothing as far as the total system cost is concerned.)
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Who is going to do the circuit design, circuit validation and CAD work for these added features? And should it be in rev 1?
By the way, there is a general engineering equation that predicts the reliability of a system. It is useful to note that in the denominator of this equation is the term n (for number of parts) squared. This means that if you double the number of parts, you have reduced the reliability of your system by a factor of four.
-AC