WHAT IS SPI? | DIY SPI in 74 series logic!

[@overkillprojects8091]

This video took longer than I wanted - I switched from Adobe Premiere/AE/etc to Davinci Resolve and there is some learning curve. Hoping to get to the point where I can release at least one video per week!

[@tomasparrado873]

Under-rated video and from a quick look, under-rated channel. Virtualy no-one in the industy cares about the terms, but they do value consistancy. I think a lot of the resistance comes from the free-for-all on new naming; manager/subordinate, controller/peripheral, host/client, and of course master/slave will be found in dataseets and our schematics for the next few decades. I'm on board with changing it, I just want to concensous

[@theodorepollock1273]

I love the sound of ICs in their tube too

[@gumbykevbo]

But I HATE the sound of IC's pouring out of the tube when I pick one up with the end stopper (thumb tack?) missing!

[@Enigma758]

Good video! I love your shirt!

[@DeepankarMaithani]

at 16:16 what is the issue you are talking about. Can you please elaborate the explanation is not clear

[@overkillprojects8091]

Of course! In the scenario I'm talking about, I am loading the register directly from my power rails. Each of the I/O pins is tied either to 0 or 5V (or actually 3.3V in this case, cf. schematic) and I will tell the IC to load those values into the register, i.e. the pins will be input pins. Now suppose I load the data 00000010 where 0 is low voltage (ground), and 1 is high voltage. After that data is loaded into the register, I can shift the values in either direction with the 74HC299. If I shift right once, and I have the left input tired to ground, the register will look like 00000001 Now imagine trying to output this data on the I/O pins: they are still connected to my power rails as 00000010 so the rightmost two pins (the two LSBs) will have using voltages. In particular, the 299 will be outputting a 1 on the rightmost pin and it will be connected directly to ground via a jumper (0 ohm connection). As a result, it will dump as much current as it can directly into ground, which can easily damage the 299. This is what I'm avoiding by removing the jumpers after loading the register. Incidentally, I could also have connected the registers to the power rails using very high value resistors (maybe 1M ohm, although you could probably do much less) to effectively reduce that current to a trivial value, but I didn't have them sitting on the desk at the time :-P

[@DeepankarMaithani]

@@overkillprojects8091 thanks for the detailed explanation.

[@mdanieltays]

@@overkillprojects8091 I don't get it, according to the datasheet just set OE1 and OE2 high, and so long as S0 and S1 are not also both high the output will go to high-impedance. No out put no problem.

[@Enigma758]

@@overkillprojects8091 I think you could use some 10k resistors as your "jumpers" and that would solve the problem.

[@jj74qformerlyjailbreak3]

If terms used to describe the sender/receiver offend you then I would guess you won't make it far in this field. I wonder what the Transistors think of this.

[@reg2590]

Hi, Found your channel whilst looking for a solution to my SN74LS299 - nice content; I would love to see more posts from you. Now perhaps you can have a go at solving my little 299 conundrum! I wish to shift a single bit left or right or circulate one bit round under the control of S0 or S1. I have a circuit that loads the single bit S0S1=H then after short delay S0S1=L. The issue is that the bit circles round in one direction but with s0/s1 change either bunches up with more bits or just just disappears. I have literally tried everything I am happy to share the circuit with you for comment. Any ideas before I turn to an ATtiny!

[@overkillprojects8091]

Hmm interesting. Yes a circuit diagram would help, but I'll set it up and look at it when I get a shot. Are you feeding serial output to serial input to get a cycle?

[@reg2590]

@@overkillprojects8091 Your interest is welcome - thanks. Here is the circuit diagram: www.dropbox.com/s/peobo9p4144jwfp/299_Shift_Left_Right.JPG?dl=0 The delay part is to ensure S0 and S1 are at a high so that a parallel read can take place. The bit on pin 7 is then captured for left/right/circulation. Hope it makes sense. regards R

[@akkudakkupl]

Master and Slave are not exclusive. Today's people are scared of words, it's sad to watch what the world have come to.

[@end.of.eternity]

the worst part is many of the chips are made in countries where literal slavery is common place yet the only thing mentioned is that "master" and "slave" are offensive words. look at the Foxconn suicides. look at the fact many people working in the chip fabrication plants live in dorms of 20-30 people and are still charged. look at the fact that in many countries in the developed world it's perfectly legal for the employer to remove wages for being "late" and then arbitrarily decide what late is. eg. if you are not at the desk ready to start work at least 15 minutes before your shift starts then you will be docked an hours pay, putting you below minimum wage legally. I put it to you that the words "master" and "slave" aren't being disallowed so people are 'comfortable', but so that people don't have a reference point for when they do become slaves again.

[@skmgeek]

Yeah, just like how you should be saying you're gay instead of saying you're really happy! Or is that too scary for you? :p

[@akkudakkupl]

@@skmgeek I do not care about that and don't take offense in it. Do whatever you want to do in your bed, but damn, grow some skin. World will be a sad place if everyone will become a snowflake crybaby.

[@ЛотариоЛибертини]

5:29 The cringe begins.