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[SOLVED] Questions bout shiftregisters (74HC575, 74HC597)

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romel_emperado

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Hi I want to interface this shift register into a micro controller but I dont understand how to properly receive the output of this register.

http://www.datasheetcatalog.org/datasheet2/4/09499zog6et5i38fsd2w00grp8ky.pdf

Description:
The ’HC597 and CD74HCT597 are high-speed silicon gate
CMOS devices that are pin-compatible with the LSTTL 597
devices. Each device consists of an 8-flip-flop input register
and an 8-bit parallel-in/serial-in, serial-out shift register. Each
register is controlled by its own clock. A “low” on the parallel
load input (PL) shifts parallel stored data asynchronously into
the shift register. A “low” master input (MR) clears the shift
register. Serial input data can also be synchronously shifted
through the shift register when PL is high.
Click to expand...

yes I understand this part but Im confused about how the MCU receive it's output from it's parallel input.
it looks like a 1 wire method.. pls help :)

the register model is CD74HCT597
 
Last edited:

Re: Questions About some shiftregisters

this is the schematic I want to do
S01 - SO5 are button/switch..

the input of this register is 8bits.. I have a feeling that the output of this register only one wire and receive it bit by bit..

the schematic attached..
 

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Re: Questions About some shiftregisters

You can also check **broken link removed**
scroll down to the middle Using the 74HC597 – Read an 8-bit DIP Switch
 
Re: Questions About some shiftregisters

Hi all,, thanks so much..

Is there any simulator where I can test this? it's not in proteus.. is there any sub model of this in proteus?

Im confused about this SPI term if it is really uses the SPI module of the PIC.. I think it ca be done by software in collecting the data..

---------- Post added at 16:21 ---------- Previous post was at 16:17 ----------

ok according to the link of alexan_e its software SPI.. still reading..
 

Re: Questions About some shiftregisters

Proteus has both 74HC597 and 74HCT597

---------- Post added at 17:24 ---------- Previous post was at 17:22 ----------

you need a clock and a data input, it resembles the SPI protocol but you do it manually using two pins, you change the state of one pin as a clock to shift the data and you read the data using the other pin, then shift one more and read again until you read all the bits
 

Re: Questions About some shiftregisters

thanks I was searching in proteus with CD74HC597..

I can see now in proteus without the CD prefix
 

Re: Questions About some shiftregisters

how come google is not giving me this site.. I already gone in searching up to page 10 of google
Click to expand...
The secret is to identify the right terms with sufficient selectivity. You can e.g. try "shiftregister io" and get mostly microprocessor related hits on the first page.
 
Re: Questions About some shiftregisters

FvM said:
The secret is to identify the right terms with sufficient selectivity. You can e.g. try "shiftregister io" and get mostly microprocessor related hits on the first page.
Click to expand...

thanks so much... actually I was searching since yesterday.. thanks to you guys..
 

Re: Questions About some shiftregisters

alexan_e said:
Proteus has both 74HC597 and 74HCT597

---------- Post added at 17:24 ---------- Previous post was at 17:22 ----------

you need a clock and a data input, it resembles the SPI protocol but you do it manually using two pins, you change the state of one pin as a clock to shift the data and you read the data using the other pin, then shift one more and read again until you read all the bits
Click to expand...

I cannot get it work.. ;( ;(

this is my code I don't know what I have missed

PORT initialization
PHP: 
#define IN_LATCH 	PORTDbits.RD0 //to shift the parallel port input pin states (D0-D7) to the parallel register
#define PLOAD 		PORTDbits.RD1 //move the data present in the parallel input register to the serial shift register
#define CLOCK 		PORTDbits.RD2 //to shift the bits out on the serial data output pin 9
#define DATA_INPUT	PORTDbits.RD3 //data line input



PHP: 
int get_data()
{
	int data = 0,i;

/* latch input PINs */
	IN_LATCH = 0; 
	delayms(1);
	IN_LATCH = 1;

    PLOAD = 0; //move data to serial shift register

	for (i=7; i>=0; i--)
	{
	
		toggle_clock(); //clock out 
		if(DATA_INPUT)
		data |= (1 << i); //store data received
	
	}
	PLOAD = 1;
	return data;


}


void toggle_clock()
{
   CLOCK = 0;
   delayms(1);
   CLOCK = 1;
}


PIN 9 of the register is not doing anything....
 

Re: Questions About some shiftregisters

bigdogguru said:
Hi Romel,

Here are a few more examples of using a shift register with C source code:

Using shift registers to extend the microcontroller I/O

Can you move over? The 74HC595 8 bit shift register - Arduino but nice tutorial

LED matrix using shift registers

Hope they help,

BigDog
Click to expand...

These are nice tutorials but they describe the serial to parallel conversion using 74HC595, Romel is asking for parallel to serial using 74HC597

Alex

---------- Post added at 01:07 ---------- Previous post was at 00:39 ----------



operation of 74HC597

Set DS to 0 (output) can be hardwired
Set MR to 1 (output) can be hardwired
Set STCP to 0 (output) needs to be toggled
Set PL to 1 (output) needs to be toggled
Set SHCP to 0 (output) needs to be toggled

to load data
Set STCP to 1
delay 1us
Set STCP to 0 (load flip flop)
delay 1us
Set PL to 0
delay 1us
Set PL to 1 (parallel load)

now bit 7 is already available for read
toggle clock SHCP (to 1 and then again to 0)
now bit 6 is available for read
toggle clock SHCP (to 1 and then again to 0)
....
 
Re: Questions About some shiftregisters

alexan_e said:
These are nice tutorials but they describe the serial to parallel conversion using 74HC595, Romel is asking for parallel to serial using 74HC597

Alex

---------- Post added at 01:07 ---------- Previous post was at 00:39 ----------

Set DS to 0 (output) can be hardwired
Set MR to 1 (output) can be hardwired
Set STCP to 0 (output) needs to be toggled
Set PL to 1 (output) needs to be toggled
Set SHCP to 0 (output) needs to be toggled

to load data
Set STCP to 1
delay 1us
Set STCP to 0 (load flip flop)
delay 1us
Set PL to 0
delay 1us
Set PL to 1 (parallel load)

now bit 7 is already available for read
toggle clock SHCP (to 1 and then again to 0)
now bit 6 is available for read
toggle clock SHCP (to 1 and then again to 0)
....
Click to expand...


Excellent..!!! Thanks so much.. The initialization value of output was what I have missed!!! Thanks so mucH!!




this initialization did the trick.. :-D:-D:-D:-D:-D:-D

PHP: 
Set DS to 0 (output) can be hardwired
Set MR to 1 (output) can be hardwired
Set STCP to 0 (output) needs to be toggled
Set PL to 1 (output) needs to be toggled
Set SHCP to 0 (output) needs to be toggled
 

Re: Questions About some shiftregisters

now Im in the output shift register.. 75HC595

We use the 595 by presenting a bit of data on the serial data input pin 14 (DS) and then toggling the shift register clock input pin 11(SH_CP) as shown in Figure 5. We do this for the 8-bits that we want to shift into the register, then we toggle the shift register clock input pin 12 (ST_CP) to cause the 595 to move the data from the serial shift register to the parallel output register. We can hook these in series so that the serial data output line pin 9 is connected to the next 595s serial data input pin 14 (DS). The only difference is that we shift in 16-bits instead of 8 as with the single 595.
Click to expand...


but why 16bits and we have only 8bits paralled output?
 

Re: Questions About some shiftregisters

I'm not sure what you are asking.
Are you referring to a specific article/circuit?
Each 74HC595 has an output of 8 bit, if you want more you can daisy chain more chips to get 16,24 or more outputs all controlled by one serial input.

Alex
 

Re: Questions About some shiftregisters

the quoted text were from this site

**broken link removed**

---------- Post added at 11:33 ---------- Previous post was at 11:29 ----------

in daisy chain output the Q' pin for the serial out must be configure also or it is automatically clock the data?
 
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Re: Questions About some shiftregisters

the quoted text describes the operation of more than one chips connected together, a circuit that uses that is described a few lines below in the article, the schematic is

**broken link removed**
 
Re: Questions About some shiftregisters

check this
**broken link removed**

data is automatically clocked...
 
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