Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.arch.embedded > #31845

Re: UART connection between ATSAMD20 and ATtiny4313

From pozz <pozzugno@gmail.com>
Newsgroups comp.arch.embedded
Subject Re: UART connection between ATSAMD20 and ATtiny4313
Date 2023-04-26 22:44 +0200
Organization A noiseless patient Spider
Message-ID <u2c2eu$1hfgr$2@dont-email.me> (permalink)
References <u2be3n$1a5nq$1@dont-email.me> <8c53b82a-f075-4b51-98bd-792221acbe60n@googlegroups.com>

Show all headers | View raw

Il 26/04/2023 18:26, Rick C ha scritto:
> On Wednesday, April 26, 2023 at 10:57:01 AM UTC-4, pozz wrote:
>> I'd like to use async UART to let these MCUs communicate.
>> The protocol will be request-response with the request generated by the
>> SAM MCU. The baudrate will be 38400bps.
>>
>> I'd like to use internal oscillator of ATtiny4313, while the SAM will
>> use an external 32.768kHz crystal (that is multiplied by internal PLL to
>> reach 48MHz).
>>
>> I'm not sure if this scenario can work well. My concerns are related to
>> the internal oscillator of ATtiny4313 that hasn't a good accuracy over
>> temperature and life.
>>
>> The tiny MCU will be supplied by 3.3V and its temperature will be in the
>> range 0-80°C.
> 
> I don't get what your question is.  You seem to understand the concepts.  You don't tell us the relevant data however.  What does the data sheet say about the frequency variability of the internal clock over PVT (process, voltage and temperature)?  I assume you are aware that the 3.3V supply will have an accuracy and an RC clock rate can be voltage dependent.  It depends on how they designed the circuit.  There are techniques for removing most of the voltage dependency, if they used them.

ATtiny4313 datasheet[1] says the internal oscillator is factory 
calibrated with an accuracy of ±10% at Vcc=3V and 25°C temperature. This 
accuracy can be reduced to ±2% at a fixed voltage and a fixed 
temperature with a user calibration.

> 
> You can always use the bit times of the SAM to adjust the bit rate on the ATtiny.  That used to be part of the protocol for low data rate modems.  The first characters sent were AT if I recall, which give good edges to time to measure the bit rate.  At 38400 bps this might be a bit tricker, it depends on your instruction rate.  A bit time is just 26 us.  Will this be a software UART, or a hardware unit?
> 

I will use the interal UART peripheral of ATtiny4313. I can't add too 
much code, the Flash memory is almost full. I wanted to know if the 
figures shown on the datasheet guarantee good communication between the 
the MCUs. It seems this isn't the case.


[1] https://ww1.microchip.com/downloads/en/DeviceDoc/doc8246.pdf

Back to comp.arch.embedded | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

UART connection between ATSAMD20 and ATtiny4313 pozz <pozzugno@gmail.com> - 2023-04-26 16:56 +0200
  Re: UART connection between ATSAMD20 and ATtiny4313 David Brown <david.brown@hesbynett.no> - 2023-04-26 17:57 +0200
    Re: UART connection between ATSAMD20 and ATtiny4313 pozz <pozzugno@gmail.com> - 2023-04-26 22:40 +0200
      Re: UART connection between ATSAMD20 and ATtiny4313 Grant Edwards <invalid@invalid.invalid> - 2023-04-26 21:00 +0000
        Re: UART connection between ATSAMD20 and ATtiny4313 Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-26 17:20 -0700
        Re: UART connection between ATSAMD20 and ATtiny4313 pozz <pozzugno@gmail.com> - 2023-04-27 10:15 +0200
  Re: UART connection between ATSAMD20 and ATtiny4313 Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-26 09:26 -0700
    Re: UART connection between ATSAMD20 and ATtiny4313 pozz <pozzugno@gmail.com> - 2023-04-26 22:44 +0200
      Re: UART connection between ATSAMD20 and ATtiny4313 Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-26 17:10 -0700
        Re: UART connection between ATSAMD20 and ATtiny4313 David Brown <david.brown@hesbynett.no> - 2023-04-27 09:17 +0200
        Re: UART connection between ATSAMD20 and ATtiny4313 pozz <pozzugno@gmail.com> - 2023-04-27 10:28 +0200
          Re: UART connection between ATSAMD20 and ATtiny4313 Andrew Smallshaw <andrews@sdf.org> - 2023-04-27 13:28 +0000
            Re: UART connection between ATSAMD20 and ATtiny4313 Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-27 09:22 -0700
              Re: UART connection between ATSAMD20 and ATtiny4313 David Brown <david.brown@hesbynett.no> - 2023-04-28 09:48 +0200
                Re: UART connection between ATSAMD20 and ATtiny4313 Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-28 01:55 -0700
            Re: UART connection between ATSAMD20 and ATtiny4313 Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2023-04-27 20:18 +0300
              Re: UART connection between ATSAMD20 and ATtiny4313 Ulf Samuelsson <ulf.r.samuelsson@gmail.com> - 2023-04-27 23:03 +0200
                Re: UART connection between ATSAMD20 and ATtiny4313 Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2023-04-28 09:58 +0300
              Re: UART connection between ATSAMD20 and ATtiny4313 Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-27 17:45 -0700
                Re: UART connection between ATSAMD20 and ATtiny4313 Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2023-04-28 10:00 +0300
                Re: UART connection between ATSAMD20 and ATtiny4313 Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-28 00:21 -0700
                Re: UART connection between ATSAMD20 and ATtiny4313 Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2023-04-28 11:43 +0300
                Re: UART connection between ATSAMD20 and ATtiny4313 Ulf Samuelsson <ulf.r.samuelsson@gmail.com> - 2023-04-28 11:10 +0200
                Re: UART connection between ATSAMD20 and ATtiny4313 Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2023-04-28 17:26 +0300
                Re: UART connection between ATSAMD20 and ATtiny4313 Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-28 02:14 -0700
                Re: UART connection between ATSAMD20 and ATtiny4313 Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-28 02:19 -0700
                Re: UART connection between ATSAMD20 and ATtiny4313 David Brown <david.brown@hesbynett.no> - 2023-04-28 14:51 +0200
                Re: UART connection between ATSAMD20 and ATtiny4313 Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-28 16:41 -0700
                Re: UART connection between ATSAMD20 and ATtiny4313 David Brown <david.brown@hesbynett.no> - 2023-04-29 18:01 +0200
                Re: UART connection between ATSAMD20 and ATtiny4313 Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-30 02:37 -0700
          Re: UART connection between ATSAMD20 and ATtiny4313 Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-27 09:02 -0700
            Re: UART connection between ATSAMD20 and ATtiny4313 David Brown <david.brown@hesbynett.no> - 2023-04-28 15:01 +0200
              Re: UART connection between ATSAMD20 and ATtiny4313 Rick C <gnuarm.deletethisbit@gmail.com> - 2023-04-28 16:44 -0700
                Re: UART connection between ATSAMD20 and ATtiny4313 David Brown <david.brown@hesbynett.no> - 2023-04-29 17:59 +0200
  Re: UART connection between ATSAMD20 and ATtiny4313 pozz <pozzugno@gmail.com> - 2023-05-03 18:16 +0200
    Re: UART connection between ATSAMD20 and ATtiny4313 Rick C <gnuarm.deletethisbit@gmail.com> - 2023-05-03 09:40 -0700
      Re: UART connection between ATSAMD20 and ATtiny4313 pozz <pozzugno@gmail.com> - 2023-05-04 10:34 +0200
        Re: UART connection between ATSAMD20 and ATtiny4313 David Brown <david.brown@hesbynett.no> - 2023-05-04 12:31 +0200
          Re: UART connection between ATSAMD20 and ATtiny4313 pozz <pozzugno@gmail.com> - 2023-05-05 10:51 +0200
            Re: UART connection between ATSAMD20 and ATtiny4313 David Brown <david.brown@hesbynett.no> - 2023-05-05 12:59 +0200
              Re: UART connection between ATSAMD20 and ATtiny4313 pozz <pozzugno@gmail.com> - 2023-05-05 18:01 +0200
                Re: UART connection between ATSAMD20 and ATtiny4313 Dimiter_Popoff <dp@tgi-sci.com> - 2023-05-05 19:52 +0300
                Re: UART connection between ATSAMD20 and ATtiny4313 pozz <pozzugno@gmail.com> - 2023-05-07 23:20 +0200
                Re: UART connection between ATSAMD20 and ATtiny4313 Rick C <gnuarm.deletethisbit@gmail.com> - 2023-05-05 11:37 -0700
                Re: UART connection between ATSAMD20 and ATtiny4313 pozz <pozzugno@gmail.com> - 2023-05-07 23:21 +0200
                Re: UART connection between ATSAMD20 and ATtiny4313 David Brown <david.brown@hesbynett.no> - 2023-05-08 08:37 +0200
                Re: UART connection between ATSAMD20 and ATtiny4313 pozz <pozzugno@gmail.com> - 2023-05-08 09:24 +0200
            Re: UART connection between ATSAMD20 and ATtiny4313 Grant Edwards <invalid@invalid.invalid> - 2023-05-05 20:16 +0000
              Re: UART connection between ATSAMD20 and ATtiny4313 pozz <pozzugno@gmail.com> - 2023-05-07 23:17 +0200
                Re: UART connection between ATSAMD20 and ATtiny4313 Rick C <gnuarm.deletethisbit@gmail.com> - 2023-05-07 14:27 -0700
                Re: UART connection between ATSAMD20 and ATtiny4313 David Brown <david.brown@hesbynett.no> - 2023-05-08 08:34 +0200
                Re: UART connection between ATSAMD20 and ATtiny4313 Dimiter_Popoff <dp@tgi-sci.com> - 2023-05-08 13:46 +0300
                Re: UART connection between ATSAMD20 and ATtiny4313 pozz <pozzugno@gmail.com> - 2023-05-08 09:38 +0200
                Re: UART connection between ATSAMD20 and ATtiny4313 Grant Edwards <invalid@invalid.invalid> - 2023-05-08 14:12 +0000
                Re: UART connection between ATSAMD20 and ATtiny4313 pozz <pozzugno@gmail.com> - 2023-05-08 18:13 +0200
                Re: UART connection between ATSAMD20 and ATtiny4313 Rick C <gnuarm.deletethisbit@gmail.com> - 2023-05-08 11:39 -0700
                Re: UART connection between ATSAMD20 and ATtiny4313 pozz <pozzugno@gmail.com> - 2023-05-09 17:04 +0200
                Re: UART connection between ATSAMD20 and ATtiny4313 Rick C <gnuarm.deletethisbit@gmail.com> - 2023-05-09 14:32 -0700
                Re: UART connection between ATSAMD20 and ATtiny4313 pozz <pozzugno@gmail.com> - 2023-05-10 08:55 +0200
                Re: UART connection between ATSAMD20 and ATtiny4313 Grant Edwards <invalid@invalid.invalid> - 2023-05-08 19:09 +0000
                Re: UART connection between ATSAMD20 and ATtiny4313 pozz <pozzugno@gmail.com> - 2023-05-09 17:08 +0200
                Re: UART connection between ATSAMD20 and ATtiny4313 Rick C <gnuarm.deletethisbit@gmail.com> - 2023-05-08 07:32 -0700
                Re: UART connection between ATSAMD20 and ATtiny4313 pozz <pozzugno@gmail.com> - 2023-05-08 18:27 +0200
                Re: UART connection between ATSAMD20 and ATtiny4313 Rick C <gnuarm.deletethisbit@gmail.com> - 2023-05-08 11:52 -0700
                Re: UART connection between ATSAMD20 and ATtiny4313 pozz <pozzugno@gmail.com> - 2023-05-09 16:52 +0200
                Re: UART connection between ATSAMD20 and ATtiny4313 Grant Edwards <invalid@invalid.invalid> - 2023-05-09 15:10 +0000
                Re: UART connection between ATSAMD20 and ATtiny4313 Rick C <gnuarm.deletethisbit@gmail.com> - 2023-05-09 14:29 -0700
        Re: UART connection between ATSAMD20 and ATtiny4313 Rick C <gnuarm.deletethisbit@gmail.com> - 2023-05-04 06:21 -0700
          Re: UART connection between ATSAMD20 and ATtiny4313 pozz <pozzugno@gmail.com> - 2023-05-05 11:02 +0200

csiph-web