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Shift Register IC's 74HC164, 74HC165 And 74HC595
Posted: Wed Aug 11, 2021 11:03 am
by EngineeringCal
Hi
Going to be programming the serial in/parallel out one.
What is TTL ? One board with shift register on it says it is TTL. Others say SPI or I2C.
Using PIC 16F84A. 8 LED mini board.
Can post code.
Any tips about this please?
Have a nice day
Re: Shift Register IC's 74HC164, 74HC165 And 74HC595
Posted: Wed Aug 11, 2021 3:09 pm
by CeaSaR
TTL is Transistor - Transistor - Logic. Most times it is associated with 0-5 levels. Here is a Wiki to get you started:
https://en.wikipedia.org/wiki/Transisto ... stor_logic
Re: Shift Register IC's 74HC164, 74HC165 And 74HC595
Posted: Wed Aug 11, 2021 5:43 pm
by EngineeringCal
Thanks CeaSaR
Here are the links for the three boards with shift registers we will be using.
https://www.futurlec.com/Mini_74HC595.shtml
That one says 'SPI control' (input) and 'output bits' guess those are TTL.
https://www.futurlec.com/Mini_TPIC6B595.shtml
This says 'a serial stream of data and converts this to a 8-bit standard TTL output.' Ooops! Looks like serial stream (bits) and TTL are different.
https://www.futurlec.com/Mini_74165.shtml
This one says '8 standard TTL inputs and converts these to a serial output stream for connection to most microcontrollers'
We will have to think about that for awhile.
Any tips on this would be welcome.
Re: Shift Register IC's 74HC164, 74HC165 And 74HC595
Posted: Wed Aug 11, 2021 11:15 pm
by dyarker
TTL refers to voltage levels and impedance of the serial stream. (about 0 and almost +5V)
As opposed to an RS-232 (upto +25V downto -25V)serial, or current loop (+20mA / -20mA) serial.
Cheers,