right this isnt for a project but is there a way to divide a fixed no by a variable binary number in digital electronics without using a microcontroller? just ocoured to me that ive never seen anything on how to do this in text books and i cant find anything on the web and this is what you would have to use in period to frequency converters for fan speeds etc
I've seen something similar using a look-up table in eprom. It was a very-low-speed tacho. A xl clock, counter for a fraction of a revolution (like one gear tooth to the next), used the count as an address to read, then displayed the byte value as feet/min or whatever. About 6 logic chips (+ the eprom), LCD display.
the next question. im making an eprom programmer but how do i make the thing to burn to the rom? i had a look on google but was probably looking for the wrong thing i understand how it writes to the eprom but not how to make a damn image to burn to the rom. thanks for the help tho
You've got to work out a formula. Say 2 pulses/rev, so 2 pulses/min = 1 rpm 10,000 pulses/min = 166.7 pulses/sec = 6mS period = 5000rpm 1000rpm = 30mS period So you fiddle a clock speed (divide-by-n chip) to count to the highest memory address in 30mS, and put 1000 in that address (adjust for the minimum speed you want). Then use Basic to generate the data for each address. The low addresses will have the fastest speeds (shorter period, lower count). Does that make sense? I'm sure I've got a Maplin car tacho circuit that might work for fans, I'll dig it out. That one counted pulses in a fixed time, so much simpler. Used a 555 astable to start and stop each count
then there is the route of creating your own division unit out of gates But the eeprom takes a lot less space and time.
no u misunderstood my second question i meant what do u use to make any file to burn to an eprom sorry i didnt reply sooner been ill EDIT thx for the diags cpemma might build 1 ne ways cos i dont like running mbm or any of those things due to horrible bleeping sounds when my cpu overheats when playing games and i cant be bothered to fiddle oh and hardware is always so much better than software
Depends on the burner hardware and software (RTBM), but can be just a list of the numbers in hex in a text file on disk. Bit like a BIOS upgrade bin file. You can use Basic to write the file. This might help.
