MC14489 Display Help

DrAnalog

I have a project which requires that I shift in data from a counter, then evaluate the count and display using 7-segment display. I can shift the data in using 74HC165 shift registers,, shift out to an MC14489 display driver, enter BCD data through thumbwheel switches. I don't know enough to convert the binary counter data to something that can be used to drive the display. Binary to BCD or binary to decimal? I'm very new at this, so any help or suggestions on were I might look to educate myself will be very much appreciated.
Thanks for any help,
Klaus

[noparse][[/noparse]Subject Added]

Post Edited By Moderator (Chris Savage (Parallax)) : 3/26/2008 2:04:33 PM GMT

bulkhead

This is to be done with a stamp right? The shifted in data "binary counter data" is represented on the stamp as a "byte" of data, which automatically can be a "decimal" number or a "binary" number. The data is the same, it's just the representation that's different. I'm looking at the MC11489 data sheet and it seems to me that it could be as easy as passing out the input byte you get from the shift register back to the MC11489 since it has an SPI interface. The MC11489 datasheet says it can drive 5.5 digits with a single chip using multiplexing, so it should have some way of perhaps decoding the number you pass it (say, $FFFF) to a BCD, then to the actual 7 segment pattern.

I would suggest reading the datasheets to see if this is possible. If it isn't you could look up some simple binary to BCD or binary to <whatever the MC11489 takes> conversions and implement them in pbasic. If this project isn't going to use a stamp, which I think it may likely not need, you could probably find hardware that does this (just google bineary to BCD IC or something, for example).

Also edit your original post to have a title describing your question as it will get it answered much more promptly.

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DrAnalog

Thanks very much for your reply. I should have been more specific in what I am trying to accomplish. The counter is counting pulses from a quartz crystal inside a vacuum chamber that changes frequency as material is deposited on it. I want to display the thickness of the deposited material. There are some variables, such as density of the material, which have to be accounted for in the program. This is why I am using the BS2e. There are also other functions, such as predicting crystal life, that I need the BS2 for. I am always subtracting the new frequency count from the previous one, then adding the result once per second or so. This relates to thickness of deposited material. I can also display deposition rate with the data. I just did not know how to take the result of the binary subtraction and display it.