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Discussion Groups | AVRclub | Triggered Inputs?
Atmel AVR Microcontroller discussion group.
Triggered Inputs? - Rompf Tobias ZFS MKK - Sep 15 7:10:00 2004
Hey Folks,
are the Ports of the Atmega 128 triggered in any way? (sure they are,
but how good)
Or do you consider an external Trigger?
I wanna be able to use input Voltages from 5 to 30 V.
Thanx in advance
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are the Ports of the Atmega 128 triggered in any way? (sure they are,
but how good)
Or do you consider an external Trigger?
I wanna be able to use input Voltages from 5 to 30 V.
Thanx in advance
(You need to be a member of avrclub -- send a blank email to avrclub-subscribe@yahoogroups.com )
Re: [AVR club] Triggered Inputs? - Dave VanHorn - Sep 15 10:13:00 2004
At 06:10 AM 9/15/2004, Rompf Tobias ZFS MKK wrote:
>Hey Folks,
>
>are the Ports of the Atmega 128 triggered in any way? (sure they are,
>but how good)
What do you mean by "trigger"?
(You need to be a member of avrclub -- send a blank email to avrclub-subscribe@yahoogroups.com )
>Hey Folks,
>
>are the Ports of the Atmega 128 triggered in any way? (sure they are,
>but how good)
What do you mean by "trigger"?
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Re: Triggered Inputs? - Graham Davies - Sep 15 16:56:00 2004
--- In avrclub@avrc..., "Rompf Tobias ZFS MKK"
<Tobias.Rompf@z...> wrote:
> are the Ports of the Atmega 128
> triggered in any way? ...
> I wanna be able to use input
> Voltages from 5 to 30 V.
I don't know if these questions were fully answered or not, so I will
have a go.
I assume you're asking first if the ATmega128 has schmitt trigger
inputs. I have checked the ATmega64 data sheet, because that's all I
have with me, and it shows a schmitt trigger in the circuit diagram
of the "General Digital I/O" ports. The only mention of a hysteresis
value is in the electrical characteristics of the two-wire serial
bus. It is given as 5% of VCC, which isn't very much. You should
check the ATmega128 data sheet.
When you say you want to use input voltages of 5 to 30 volts, I don't
know what this has to do with schmitt trigger inputs. You can't do
this, schmitt trigger or not. The Absolute Maximum Ratings section of
the data sheet gives the voltage on I/O pins with respect to ground
as no lower than -1.0 volts and no higher than VCC + 0.5 volts. This
is because there are static protection diodes on the inputs. You will
need an external level translator.
Graham.
(You need to be a member of avrclub -- send a blank email to avrclub-subscribe@yahoogroups.com )
<Tobias.Rompf@z...> wrote:
> are the Ports of the Atmega 128
> triggered in any way? ...
> I wanna be able to use input
> Voltages from 5 to 30 V.
I don't know if these questions were fully answered or not, so I will
have a go.
I assume you're asking first if the ATmega128 has schmitt trigger
inputs. I have checked the ATmega64 data sheet, because that's all I
have with me, and it shows a schmitt trigger in the circuit diagram
of the "General Digital I/O" ports. The only mention of a hysteresis
value is in the electrical characteristics of the two-wire serial
bus. It is given as 5% of VCC, which isn't very much. You should
check the ATmega128 data sheet.
When you say you want to use input voltages of 5 to 30 volts, I don't
know what this has to do with schmitt trigger inputs. You can't do
this, schmitt trigger or not. The Absolute Maximum Ratings section of
the data sheet gives the voltage on I/O pins with respect to ground
as no lower than -1.0 volts and no higher than VCC + 0.5 volts. This
is because there are static protection diodes on the inputs. You will
need an external level translator.
Graham.
(You need to be a member of avrclub -- send a blank email to avrclub-subscribe@yahoogroups.com )