Parallel to Serial Conversion: IC 74165 & 2 Clock Purpose

[kschong]

hi, may i know how to control IC 74165? What is the purpose of this 2 clock? i need a IC which can transfer 8 bit data from parallel to serial, got any suggestion?

 

[vk6kro]

That chip would be OK.

It has two clock inputs so that one of them can control clock input from the other. It is really just one clock.

It can load from parallel inputs and send this data out as serial.

The Fairchild data sheet explains it pretty well.

 

[berkeman]

hi, may i know how to control IC 74165? What is the purpose of this 2 clock? i need a IC which can transfer 8 bit data from parallel to serial, got any suggestion?

Adding a question to vk6kro's advice, what do you want for the serial data stream? Do you want it in some standard format/interface like SCI (RS-232) or SPI or I2C, or some other? What is the overall context of your question?

 

[kschong]

Actually now i m doing a project about the Cyclic Redundancy Check (CRC), i need the IC 74165 for the convert the parallel data into serial data. Unfortunately, i m don know how to control the two clock to let the data transfer into serial. For this CRC project, can i use the RS 232??

 

[berkeman]

Actually now i m doing a project about the Cyclic Redundancy Check (CRC), i need the IC 74165 for the convert the parallel data into serial data. Unfortunately, i m don know how to control the two clock to let the data transfer into serial. For this CRC project, can i use the RS 232??

No, if you are making a CRC state machine, there is no need to have the serial data in any particular comm format. You are just going to be putting it through your CRC circuit, right?

What kind of logic are you going to use to control your state machine? Where do the parallel bytes come from? Where are you going to shift out the final CRC? How wide will it be?

Is this a paper-only design, or are you going to simulate it, or are you going to build it up?

 

[vk6kro]

Unfortunately, i m don know how to control the two clock to let the data transfer into serial.

You need to download a data sheet for this chip.

If you hold pin 15 low and feed the clock into pin 2, it will clock continuously. Making pin 15 high will stop the clocking even if pin 2 continues to get clock pulses.

Making pin 1 low will load the parallel data from the 8 data input pins. Making pin 1 high will allow clocking of the data towards the serial output, pin 9.
Clocking must be done at the right baud rate for the serial output to be at the right speed.