connecting the 74594 shift register to the PIC16f1508 micrcontroller

Hello to all

I want to interface the 74594 shift register to my pic16f1508 microcontroller, but I am a little bit confused about the clock pins of the shift register.

Actually the shift register is consist of two clock pins one is for the shift register and the other is for the storage register. So I want to know that which pins of the pic16f1508 microcontroller should I use to provide the clock pulse to the shift register.

I am thinking that I should use the timers of the micrcontroller to provide the clock pulse to the shift register and the storage register but in some cases on the site I have saw that the people have used normal i/p pins for the clock source as here:

http://www.romux.com/tutorials/pic-tutorial/shift-registers

and http://www.oocities.org/mindtan2000/PIC.html

So I want to know that how can I generate the clock pulses from the general i/p pins and can I use the timers for this purpose or how the timers can be used as the clock source for the peripherals of the outside world.


Thank you

You can use any pin as clock, just set it to 1 and then back to 0.

You can check **broken link removed**
and https://www.edaboard.com/threads/222857/#post949459

Alex

One need to configure the Pin as output in the micro-controller and as alexan_e said write the 1 and 0 to that pin to get your shift register working....most important is what is time to this 1 or 0 ....i.e. delay for which the high and low need to present... best practice is to have 50% duty cycle....but of-course based on the specification of clock frequency of the shift register....one need set the delay for port pin high and low....In the typical case like port pin set in while(1) one need to very cautious about the delay and timer interrupt flag clearing....also board parameter also effect significantly if one uses frequency of operation for shift register very high ....

Good Luck

I don't think there will be a need for any delay, the 74HC595 can work fine with very high clock speeds unless of course there is a problem with the mcu generating a clear pulse.

According to the datasheet of 74HC595 the clock pin can work fine with pulses that have duration over 20ns (5v supply), that is quite fast.

Alex

ok so connect any pin for the clock pulse.

you mean that connect any pin to the clock pulse and than serially enter the data by putting the bit and than toggling the clock from high to low i.e. form 1 to 0 and the data will be forwarded to next flipflop and than again put the next bit and than toggle the pin and the data will be inserted in this way.


am I right alexan..

Yes exactly as described in the post of my second link above

yeap

thanks again alex


But I have one more doubt if I am going to toggle in this manner than ofcourse I am not going to get the clock pulse on the clock pin of the shift register as shown in the figure 5 of this webpage which you have linked to me.

**broken link removed**


So tell me how would I get the continuous clock pulse like that shown in the figure or am I misunderstanding that.


Thanks