74HC165 Cascade of 3 Chips

Michael @ Afineol

I would like to cascade 3 74HC165 IC's. I have read the StampWorks·section on how to setup the circuit, but the programming is what has me baffled. The documentation talks about cascading 2 chips and gives example code. It references a "word" sized variable which is 16 bits or 65535.·I will need to address 24 bits or 16777215. Does anyone have example code for a BS2 to address all·3 chips.

Mike S.

D Faust

Try making a 3 byte array and storing the 24 bits to that. (it might work, I don't remember the syntax for it.) Next I would try putting 2 shiftin commands back to back. Check the syntax guide to see if there is anything about putting multiple variables. Hope This Helps.

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--DFaust

willy1067

I have the same setup in

http://forums.parallax.com/forums/default.aspx?f=5&m=181646

and I thought in the same way you are now, but it works out that you only have to send one word at a time (8 bits, 255) to each 74HC165 and keep shifting to the next chip.

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Fernando Gomez


Never compare yourself with anyone else, there will always be someone bigger·or·smaller·than you.

Chris Savage

Hello,

From the Stamp Works manual, the following code shifts in 16 bits into a word variable. But that doesn’t mean you have to deal with a word at a time.

SHIFTIN SerData, Clock, MSBPRE, [noparse][[/noparse]xInputs\16]  ' shift them in 

Any number of byte values can be shifted in with a single instruction as follows.· I hope this helps.· Take care.

SHIFTIN SerData, Clock, MSBPRE, [noparse][[/noparse]value1, value2, value3, value4, value5]

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Chris Savage
Parallax Tech Support

Chris Savage

In my example each value is a byte value. You should have one variable (byte) for each 74HC165 in the chain. I should have mentioned that before. Take care.

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Chris Savage
Parallax Tech Support

willy1067

I WAS ABLE TO GET IT WORKING LIKE THIS;

'{$STAMP BS2}
'{$PBASIC 2.5}

dat PIN 1
clk PIN 0
latch PIN 2
start:
LOW latch
SHIFTOUT dat, clk, LSBFIRST, [noparse][[/noparse]1]: SHIFTOUT dat, clk, LSBFIRST, [noparse][[/noparse]3]:· SHIFTOUT dat, clk, LSBFIRST,[noparse][[/noparse]7]:· SHIFTOUT dat, clk, LSBFIRST,[noparse][[/noparse]15]:· SHIFTOUT dat, clk, LSBFIRST,[noparse][[/noparse]31]:· SHIFTOUT dat, clk, LSBFIRST,[noparse][[/noparse]63]
PULSOUT latch, 5
LOW latch

Post Edited (willy1067) : 12/21/2007 11:02:48 PM GMT

Chris Savage

Willy,

I wonder if you’re not using the 74HC165, but rather the 74HC595? The SHIFTOUT command is not used with the 74HC165. It is, however, used with the 74HC595, and to SHIFTOUT the values from your example you could have used:

SHIFTOUT dat, clk, LSBFIRST, [noparse][[/noparse]1, 3, 7, 15, 31, 63]

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Chris Savage
Parallax Tech Support

willy1067

Yes Chris, right now I am working on the output 595 of my circuit, I will use the 165 later for input.

Can you help with this code?·· I am attaching a stepper motor to the 5th 595, I would like to move foward if pin3 is set high with a push button.· this is what I have so far,· (as I said before, I suck·as a programmer)

' {$STAMP BS2}
' {$PBASIC 2.5}

DO
Steps DATA 3, 6, 12, 9
dat PIN 1
clk PIN 0
latch PIN 2
start:
LOW latch
SHIFTOUT dat, clk, LSBFIRST, [noparse][[/noparse]0, 0, 0, 0, Steps, 0]
PULSOUT latch, 5
LOW latch
DEBUG ?IN3
IF (IN3 = 1) THEN Steps
PAUSE 1000
ELSE PAUSE 100
LOOP


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Fernando Gomez


Never compare yourself with anyone else, there will always be someone bigger·or·smaller·than you.

Post Edited (willy1067) : 12/29/2007 6:12:27 AM GMT