How do you interface a 74hc165 to a pic12f629

Hello all im new to the pic basic so be easy on me. I am trying to interface a standard 74hc165 parallel to serial shift register to a pic 12f629 im using GPIO.0 as CLK OUT , GPIO.2 as the DATA INPUT pin and a push button to load the parallel inputs on the 74hc165 via the Serial Shift/ Parallel Load pin, I have a 8 bit dip switch connected to the parallel port of the 74hc165 with 4.7k pullups and ground when switch contact is closed. I have looked at the SERIN and HSERIN and just havent had any luck yet.

You need to use SHIFTIN.


---------------------------
CMCON=7

MyByte VAR Byte

SHIFTIN GPIO.2,GPIO.0,0,[MyByte]
---------------------------

I don't have a HC165 Datasheet available, make sure the mode matches the specs of the HC165.

See PBP Manual Section 5.72

Thank you!! Works like a charm. I got most of it from the Archives. Here is a cleaned up version.

Low GPIO.0

' pin 1 of 74HC165 loads parallel port

Pause 1

High GPIO.0

' pin 1 of 74HC165 allow data to shift in

ShiftIn GPIO.2,GPIO.1,0, [VAR1\8]

'GPIO.2 to 74HC165 pin 9 and GPIO.1 to 74HC165 pin 2

Pause 1

"I got most of it from the Archives."

Is this on this forum?

I SEARCHed and could not find any other reference to 74HC165.

I am particularly interested in how the 74HC165 is wired.

Robert
:)

"See PBP Manual Section 5.72"

I get SERIN2 in my copy...? SHIFT IN is over at 5.75.

Robert
:shrug:

I have tried to interface a 16F628 with a 74HCT165 without success. I figured I should do a basic test to confirm that my code is working properly. I unplug the CK and PL pins and plug the Q7 pin on the PIC directly to power to test my code.

- when I plug Q7 to GND, I get all 0s, as expected.

- when I plug Q7 to +5V, I get all 0s and a 1 at the far right.

This is my code:

CMCON = 7
ASM
LIST
INCLUDE 'M16F62X.INC'
DEVICE PIC16F628, HS_OSC, WDT_ON, MCLR_OFF, PWRT_ON, LVP_OFF, PROTECT_OFF
XALL
NOLIST
ENDASM
INCLUDE "MODEDEFS.BAS"
TRISA = %10000000
TRISB = %00000001
DEFINE OSC 20
DEFINE SHIFT_PAUSEUS 3
DEFINE LCD_DREG PORTB
DEFINE LCD_DBIT 4
DEFINE LCD_RSREG PORTA
DEFINE LCD_RSBIT 0
DEFINE LCD_EREG PORTA
DEFINE LCD_EBIT 1
DEFINE LCD_BITS 4
DEFINE LCD_LINES 4
DATAIN VAR BIT[16]
' ----- PORTB.0 = Q7 ----- PORTB.1 = CP ----- PORTB.2 = PL -----
PAUSE 500
LOW PORTB.2 : PAUSE 3
HIGH PORTB.2 : PAUSE 3
SHIFTIN PORTB.0,PORTB.1,MSBPRE,[DATAIN\16]
LCDOUT $FE,1,BIN16 DATAIN
END

Robert
:(

Note: same results no matter what shift mode I use.

I've cut out those lines of code to simplify reading on this forum, but I repeat the shift command 4 times using each mode and display 4 lines on the LCD.

Robert
:)

Another note, I am chaining two 74HCT165s, hence 16 bits.

Ok,

I changed the data to a BYTE, reduced 16 in the shift and LCD commands down to 8 and my test signal worked.

I don't see what it did not like about having 16 bits?

Robert
:shrug:

I added one step to my testing, adding a 2nd BYTE of data in the shift and LCD commands and the test signal works good too.

So it likes 2 BYTES, but not 16 BITS, I can live with that...

I think it was Ralph that said in the PIC-TO-PIC thread, "one thing at a time".

Robert
;)

Thank you Ralph and a HUMUNGOUS thank you to Mister E for his patience with a newb like me.

Un gros bisou mon amour! :LOL:

It works like a charm now, I can flick my bits like I want to.

Robert

Hehe... sti d'fif ;)

Great to know everything is working fine now.

I'm going to write "74HCT166" in this thread, just so that the next guy that searches for that chip can find this thread.

I started out using the 166, but the 165 is also good for my application. Maybe including the word here can save someone else the headaches I had trying to get the 166 to work.

Robert
:)

Oh yeah, might as well include the other variants:

74HC166
74LS166