CREATE A 8 BIT SERIAL STREAM FROM REGISTER

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badbaud
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Posted by badbaud: Wed. Jun 1, 2016 - 04:59 AM
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I'm working with the ATTiny85 and need to generate a 8 bit serial string into a serial to parallel IC.

 

I have done this on the 8031 platform in the past but cannot figure out what commands will do the same thing in the AVR language.

 

So I put a binary number into a register, then check bit-0 to see if it is a one or a zero. I set the data in pin on the serial to parallel IC and generate a clock pulse to enter that bit.

 

And so on for all eight bits. at the end I generate a strobe pulse to output the 8 parallel bits.

 

The closest command I can find that I think would be useful would be the BLD command, if so I could use some help on how to implement it properly.

BADBAUD

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AVR Microcontrollers, megaAVR and tinyAVR
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Kartman
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Posted by Kartman: Wed. Jun 1, 2016 - 06:00 AM
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Google found this:
http://nerdralph.blogspot.com.au/2015/03/fastest-avr-software-spi-in-west.html?m=1
I googled avr spi asm

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badbaud
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Posted by badbaud: Wed. Jun 1, 2016 - 06:14 AM
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Thanks, that is what I needed.

BADBAUD

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sparrow2
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Posted by sparrow2: Wed. Jun 1, 2016 - 06:59 AM
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You should look into how the USI on the tiny85 works, it can do the job for you.

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badbaud
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Posted by badbaud: Wed. Jun 1, 2016 - 07:37 AM
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I am using PB0 thru PB2 as control lines to the SPI chip. Is USI port specific?
 

BADBAUD

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sparrow2
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Posted by sparrow2: Wed. Jun 1, 2016 - 07:51 AM
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RTFM

 

but yes they use the same IO's as the SPI

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sparrow2
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Posted by sparrow2: Wed. Jun 1, 2016 - 07:54 AM
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why not use SPI for both and then use SS (CE or what ever the names are), to control which chip you talk to.

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