nomadaz666
New Member
cpld programming rpm tricker (answered/done)
I'm new to cpld's (VERY new, as in I just started reading up on them the other day) but it looks as if it may be the answer I'm looking for.
I want to measure (count) an input shaft rpm, which pulses 8 times per revolution.
so I figured count for 250ms, divide by 2. (I know 125ms would give correct reading but I want the half rpm resolution)
I then want to display this rpm on 3 7 segment led's.
I also want a 4bit binary switch as an input (0-15) as I want to manipulate the output signal by lowering the rpm reported.
so I need to subtract this input from the measured rpm.
now to give back the correct signal I multiply this result by 8 for my new frequency.
I then send it out using the pwm 50%duty cycle at the new frequency.
If I'm understanding this correctly, CPLD's allow schematic AND vhdl code (where I can put the simple math) both to the fitter. I'd like to know what programs I need to accomplish this, how long one would guestimate the learning curve is to accomplish this. as far as the programmer goes I intend to build my own using the jtag programming method. seems simple enough.
I have drawings to maybe clear up any of my ramblings here:
**broken link removed**
**broken link removed**
I'm new to cpld's (VERY new, as in I just started reading up on them the other day) but it looks as if it may be the answer I'm looking for.
I want to measure (count) an input shaft rpm, which pulses 8 times per revolution.
so I figured count for 250ms, divide by 2. (I know 125ms would give correct reading but I want the half rpm resolution)
I then want to display this rpm on 3 7 segment led's.
I also want a 4bit binary switch as an input (0-15) as I want to manipulate the output signal by lowering the rpm reported.
so I need to subtract this input from the measured rpm.
now to give back the correct signal I multiply this result by 8 for my new frequency.
I then send it out using the pwm 50%duty cycle at the new frequency.
If I'm understanding this correctly, CPLD's allow schematic AND vhdl code (where I can put the simple math) both to the fitter. I'd like to know what programs I need to accomplish this, how long one would guestimate the learning curve is to accomplish this. as far as the programmer goes I intend to build my own using the jtag programming method. seems simple enough.
I have drawings to maybe clear up any of my ramblings here:
**broken link removed**
**broken link removed**
Last edited: