need help with a binary output from picaxe?

R

rmitch

New Member
I want to preset a 3 digit counter when it is turned on to read 998. I need to output the number in binary and make the preset pin low to preset the number on the counter ( 3 counters 3 presets).

my question is, how do i output the numbers? I dont know enough about it to find an answer by searching, ive tried.
If i were to take a stab at it i would use 4 pins and output the binary code that way right into my counter (74ls192) but how would the counter know which order the 0' s and
1's got to make the number?
I dont know where to go from here.
 
D

Dominic B

New Member
Assuming this is the right counter, I think that the counter treats Input A/pin15 as 2^0, Input B/pin1 as 2^1, Input C/pin10 as 2^2 and Input D/pin9 as 2^3.

So I dnt think it matters which picaxe output you use, but instead that you know to which Binary input the output goes to. So to preset the first as 9, the outputs connecting to pins9 and 15 on the counter should be high, the outputs to pins1 and 10 low. Therefore the counter should display 9.

Hope this helps/isn't completely wrong
 
M

Mycroft2152

Senior Member
r,

I used that chip in a model rocket launcher a long time ago. :)

With the '192, you put the binary number on the inputs then toggle the preset to "load' the numbe into the counter. If you always want to load in the same the number then just tie the inputs to ground or Vcc. Otherwiseuse thumbwheel switches or tie the inputs to a picaxe.

You may want to look at the CD4510 presettable up /down counter. It is a bit easioer to use and is very low power. Try to stay away from the LS versions of chips for battery powered devices, as they are power hogs. The "C" versions (HC and AC) of the 74xx chips are preferrd as they are low power cmos. the other option to use the CDXXXX series.

Myc
 
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