i got trouble to find the name of the CHIP where CHIP needs input from
8 pins port parallel to the chip.....if i send output 128 , the chip will give signal 1 to pin 128... if i send output 235,the chip will give signal 1 to pin 235....... the consept of the chip like TTL. 8 pins is for input from port paralel 256 pins for output of the chip 2 pins for voltage & ground thank for everything
Perhaps a PLD (programmable logic device) or FPGA (Field Programmable Gate Array) would be suitable. You would need to program the chip with the function you need.
Check out Xilinx, Altera, Actel, Lattice etc for their products and their tools to allow you to design and program the chip.
Hope that helps.
Alan
If you only wanted to drive a single pin for each value (so 128 only instead of 1 to 128), I would call this an 8-to-256 decoder. But I have never seen a standard chip with this many outputs, max I have used is
4-to-16.driving 1 to 128 on an input of 128 sounds more like a bar graph output. There are special chips for bargraphs, but I know of none with this many outputs.
So I imagine you will need to use multiple chips or use a CPLD. The logic for this CPLD will be very simple, but you need a large one just te get enough IO.
If speed is not a criterium, I think a small microcontroller with a series of shift registers for the outputs is the easiest solution.
Wat are the pins supposed to drive? If it is for LED outputs only, a multiplexing drive will save you a lot of IO. That means less chips or a much smaller CPLD. Also there are multplexing LED drivers available that can drive a lot of LED's, but you need to send those commands, not just the 8-bit value.
And if you do find a chip that matches your original request, it will likely have a more pins. It is very common for larger chips to have multiple VCC and ground pins.
-- Stef (remove caps, dashes and .invalid from e-mail address to reply by mail) Aim for the moon. If you miss, you may hit a star. -- W. Clement Stone
On 03/03/2006 the venerable snipped-for-privacy@yahoo.com.sg etched in runes:
I can do it with 17 off 74HCT154 chips! Don't fancy laying out the PCB though. Your best bet is 32 off 74HCT164 shift registers hanging on an SPI port. That could also be a fun design.
-- John B
thank's Alan Myler,Stef & John B the concept of chip is combination between AND and NOT gates the output of the chip will connected to the LED....but for advance i'll try to connect to others electronic (adding some chips) like switch ON or OFF the air conditioning,Lamps,Fan,TV,the alarm,rice cooker..etc.... sorry..if i wrong write this message... thank's for everyting
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