#avr Logs

Nov 18 2020

09:13 AM rue_mohr: --
12:36 PM nohit: --
12:46 PM TyrMactire: hello there. i'm coming from arudino writing my first program for at attint 13a, it's a little fan controller with a parallel interface. I am curious if the extra logic to check if the value changed is neccessarry or if i should just update the timer register every cycle.
12:46 PM TyrMactire: https://github.com/tyrm/stack-k3s/blob/develop/fan-control-avr/main.c
12:47 PM LeoNerd: Why the 13A, by the way? It's an absolutely /ancient/ chip with almost nothing on it
12:47 PM LeoNerd: The ATtiny412 is the current latest-tech 8pin ATtiny.. it's a muuuuch more capable chip
12:47 PM TyrMactire: it smol
12:47 PM TyrMactire: and tru-hole
12:48 PM TyrMactire: i am terrible with SMD lol
12:48 PM cehteh_: i have some tiny13a laying around as well
12:48 PM cehteh_: they work, but they are really the definition of tiny
12:49 PM LeoNerd: Oh I *have* some left over from something silly, I'm just not sure I'd ever use them now
12:49 PM cehteh_: i'd prefer a t45
12:49 PM LeoNerd: E.g. a thing I used them on before was basically a UART receiver to single PWM channel converter
12:49 PM LeoNerd: These days I'd just use a tiny412 because that actually has a real hardware USART module :)
12:49 PM cehteh_: well i i had to make some fan controler which need little code, mkay
12:49 PM TyrMactire: that's what i'm doin :D
12:50 PM cehteh_: actually iam thinking about doing that soon as well
12:50 PM LeoNerd: Also, ATtiny412 is like /half/ the price of the 13A.. even though it's newer, more capable, 4 times more Flash
12:51 PM LeoNerd: 40p each from Farnell, vs... nearly 80p for a 13A
12:51 PM cehteh_: but throwing away the tiny13 and buying a 412 is 2 times more expensvie for the same thing
12:51 PM TyrMactire: i will extaticly purchase the 412 when they release a PDIP version!
12:51 PM cehteh_: 3 times
12:51 PM LeoNerd: Ohsure; if you have existing stock of the 13A and aren't intending to make a lot of these things, .. might as well use up the old stuff
12:52 PM LeoNerd: I just wouldn't buy any new ones :)
12:52 PM LeoNerd: In fact, apart from the ATmega328PB with its dual SPI and I²C controllers, I don't think I'm likely to buy a non-XMEGA/UPDI chip any more
12:52 PM cehteh_: anyway i prefer to have timers just running if possible, rarely for special tasks i leave dedicated timers that are used only for that then, starting/stopping whatever is needed
12:53 PM cehteh_: for fan control you only need pwm right?
12:53 PM LeoNerd: I kinda keep my fingers crossed waiting on an ATmega3218, ... here's hoping
12:54 PM TyrMactire: i guess i'm curious though what the outcome of constantly updating the timer register with the same value would do vs, only updating when it's changed, if there is a convention when working at this low level
12:54 PM cehteh_: i tihnk i end my affair with avr's except for some really small playthings
12:54 PM cehteh_: TyrMactire: no idea what you are doing there
12:54 PM cehteh_: even the t13 can generate pwm in hardware
12:54 PM LeoNerd: Yah; that's about the only hardware it /does/ have, but it does have one :)
12:55 PM cehteh_: are there any tinys with onewire in hardware? guess not, didnt license it
12:55 PM LeoNerd: Dallas onewire? I haven't seen any
12:56 PM cehteh_: maybe one can use the usi for that
12:56 PM LeoNerd: Dallas onewire is a bit weird
12:56 PM LeoNerd: s/a bit/very/
12:56 PM cehteh_: yeah
12:56 PM cehteh_: *but* its usage on the other hand is nice
12:56 PM LeoNerd: I've only ever seen it on those temperature sensor things
12:56 PM LeoNerd: Does anything else actually use it?
12:57 PM cehteh_: a lot stuff uses 1w
12:57 PM cehteh_: and when you want a low pin count, low power, lots slow sensors its hardly to beat
12:58 PM LeoNerd: Ohsure, it sounds like a cute idea... but I haven't ever seen any other sensors /actually/ using it. Only the DS18x20 temperature sensors
12:58 PM LeoNerd: Whereas justabout any sort of sensor comes in an I²C form
12:58 PM cehteh_: also authentification tokens and more stuff using 1w
12:59 PM cehteh_: but 1w allows more devices on a single pin can do this parasitic power stuff and long cable lengths
12:59 PM LeoNerd: Yes... I'm aware of its on-paper benefits.
12:59 PM LeoNerd: Can you point me at anything other than the DS18x20 temperature sensor that I could buy right now?
12:59 PM cehteh_: in some was its superior to i2c and spi .... in other ways you are right, its pretty weird
12:59 PM LeoNerd: E.g. a humidity sensor
01:00 PM cehteh_: flash memories, authentication tokens, thermocouples,
01:01 PM cehteh_: well alonge the ds18b20 makes it worthwhile when you only need moderate/ambient temperature ranges
01:02 PM cehteh_: for example for the fan controller i planned i want 2 temp sensors one for ambient/inlet and one for exhaust
01:03 PM cehteh_: then pi controller to limit the exhaust temperature to some offset over the ambient temperature
01:04 PM cehteh_: methinks that would be smarter and more silent than the dumb temperature curves you do on normal mainboards
01:05 PM LeoNerd: Ohyeah, likely. Still, I'd be using a couple of I²C sensors for that I suspect...
01:08 PM cehteh_: i just use what i have ... some old tinys and ds18b20
01:09 PM cehteh_: well currently i have some fun with non embedded stuff
01:12 PM Miyu is now known as hackkitten
01:31 PM [1]MrMobius is now known as MrMobius
11:28 PM day_ is now known as day