PWM & xtiny (ATTINY3217)

Skrivo · Joined: 15 Jul 2020 Posts: 11

The company I work for requested to switch from old ATTINY84A to ATTINY3217 - we got information that ATTINY84A will be in production max. till 2025 and that is ALARM!!! The same is true for popular ATMEGA328P.....we will all need to switch to new xtiny 0 or 1 series and also to new ATMEGA 0 series which are still unfortunately unsuported in Bascom...). I am posting this information because the old ATTINYs and ATMEGAs will become totally obsolete quite soon and we all need to be aware of that fact!

As I am not very experienced I now have a problem to implement the same »dual slope« PWM output on ATTINY3217 as I use on "old" ATTINY84A where the Bascom code is the following:

'-------------------------------------------------------------------------------

Config Timer1 = Pwm , Prescale = 1 , Compare B Pwm = Clear Up ' for PMW output we choosed pin OC1B

'in registers we define mode 8 PWM: Phase & Freq. Correct (PWM frequency is ultra correct….same accuracy as XTAL)
Tccr1b.wgm13 = 1
Tccr1b.wgm12 = 0
Tccr1a.wgm11 = 0
Tccr1a.wgm10 = 0

'define PWM frequency:
Icr1 = 7999 'PWM frequency = 16000000/(prescale*(ICR1+1)*2) = 1000Hz (ultra precise)…………TIMER1 is running from 0 to 7999 and then from 7999 back down to 0 and repeating this sequence indefinitely

'run PMW with constant 25% duty cycle – PWM available on pin OC1B (PA5 on ATTINY84A)
Ocr1b = 2000 'define desired 25% PWM duty cycle on PWM output pin OC1B: OCR1B = (dutycycle*ICR1)/100

'-------------------------------------------------------------------------------

Can somebody please help me write the equivalent code for the new ATTINY3217? I need to get out this accurate 25% duty cycle PWM on pin PB0 using TCA0 timer in ATTINY3217.

(BASCOM-AVR version : 2.0.8.3 )

SZTRAD · Joined: 30 Dec 2019 Posts: 165

I probably don't understand what you're talking about, but the advantage of Bascom and its biggest advantage is that you don't really have to change anything and adjust it manually. The environment will do it for you if the selected chip has peripherals.
So pick a chip and translate, upload and use.
I haven't tested PWM yet, but I assume that Mark will not make a mistake here after many years of experience. If there is a need to test and ask specifically.

Skrivo · Joined: 15 Jul 2020 Posts: 11

albertsm · Joined: 09 Apr 2004 Posts: 5917 Location: Holland

indeed one of the big advantage is that you can change $regfile and most code will work. but that also depends on the hardware.
The timers in the normal AVR are different compared to the ones with XMega.
And the xtiny also has new kind of timers. So it is not so simply to map old functionality. but where possible all is kept the same.
Now about this question. I need to look into it. when implementing xtiny support some new hardware features were skipped (for example the usart can do irda too). and those are added depending on demand.
the timers have a lot of options as you can see from the config TCA0
i will get back on your question when i have sorted it out.

plouf · Joined: 19 Jan 2012 Posts: 78 Location: Athens,Greece

Skrivo · Joined: 15 Jul 2020 Posts: 11

plouf · Joined: 19 Jan 2012 Posts: 78 Location: Athens,Greece

to me it seems that this site takes "EOL" based on how many years is in production
but EPSECIALY mega328 is so wide spreaded in so many applications (including arduino)
which make IMPOSSIBLE to think that they stop production,at least without a replacement
for example mega328P -> 328PB

so check atmega328PB, but at any case this is not official announcement, but an ESTIMATION from
an automated system

(it says that it has live 5 years more than expected ?!) check out pic16f84A , ,, a 25+ years mcu still under production
even if newer devices are 1/10 of its price and have *10 its capabilities it is still selling because of its huge penetration in market

so as long as MICROCHIP does not issue an EOL do not expect to stop and even then will be available for at least a few years

Skrivo · Joined: 15 Jul 2020 Posts: 11

Skrivo · Joined: 15 Jul 2020 Posts: 11

albertsm · Joined: 09 Apr 2004 Posts: 5917 Location: Holland

I think that this should be the same :

Config Tca0 = Pwm , Prescale = 1 , Resolution = Normal , Compare0 = Enabled
Tca0_per = Your Icr Value
Tca0_cmp0 = Your Compare Value

output should be on compare0 output pin. you need to set this pin to output.

Skrivo · Joined: 15 Jul 2020 Posts: 11

albertsm · Joined: 09 Apr 2004 Posts: 5917 Location: Holland

the equivalent code is : Config Tca0 = Pwm_bot , Prescale = 1 , Resolution = Normal , Compare0 = Enabled , Run = On

there are actually 2 modes that do bottom/bottom i chose the single slope while you have double slope. the problem was however the RUN=ON
and that demonstrate another problem : i tried to keep syntax close to xmega. but that is not always clear.

you are right about the additional devices. i implemented them all now ; multi aci, dac, adc, etc.
except the timers. in fact the timer only implements tca. it is the last thing to do.
one note : when you manual set bits, you can not port the code. you best use the bascom syntax.

Skrivo · Joined: 15 Jul 2020 Posts: 11

albertsm · Joined: 09 Apr 2004 Posts: 5917 Location: Holland

like i wrote in another topic. first i like to fully finish the xtiny support. as you see the help is not complete yet.
after that i will add the mega devices since indeed there seem to be little of them. and for a big part they seem similar (except for memory , fuses, etc.)
the idea is to add them to xtiny add on free of charge.

SZTRAD · Joined: 30 Dec 2019 Posts: 165

Well, I'll pay extra and dare I say I'm not alone. I'm used to paying for good things.