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Discussion Groups | MSP430 | SMBus or i2c error
The purpose of this group is to foster exchange of information on the Texas Instruments MSP430 family of microcontrollers and related tools. Everyone welcome, all levels of familiarity/expertise.
SMBus or i2c error - magzky02 - Aug 17 22:39:11 2008
Hello forumers, I am using MSP430F1610 to communicate with i2c/SMBus
devices. It runs OK when the the i2c devices are working fine. But if
the device is not working/defective/not responding, my code hangs. How
do you know that there is error in i2c communication? As for now, i
place a counter to exit if the device is not responding after some
counts.
while (I2CDCTL & I2CBUSY);
I2CNDAT = 0x01;
I2CSA = 0x18; U0CTL |= MST;
I2CTCTL |= I2CSTT+I2CSTP+I2CTRX; // write
while ((I2CIFG & TXRDYIFG) == 0x0) // it hangs here if no counter
{cnt++; if (cnt > 5000){tj_id = 0x30; reak;}}
I2CDRB = 0xFE; // manufacturer id
while ((I2CTCTL & I2CSTP) == I2CSTP);
thanks,
mago
------------------------------------
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Re: SMBus or i2c error - Joerg - Aug 21 18:31:00 2008
magzky02 wrote:
> Hello forumers, I am using MSP430F1610 to communicate with i2c/SMBus
> devices. It runs OK when the the i2c devices are working fine. But if
> the device is not working/defective/not responding, my code hangs. How
> do you know that there is error in i2c communication? As for now, i
> place a counter to exit if the device is not responding after some
> counts.
>
> while (I2CDCTL & I2CBUSY);
> I2CNDAT = 0x01;
> I2CSA = 0x18; U0CTL |= MST;
> I2CTCTL |= I2CSTT+I2CSTP+I2CTRX; // write
> while ((I2CIFG & TXRDYIFG) == 0x0) // it hangs here if no counter
> {cnt++; if (cnt > 5000){tj_id = 0x30; reak;}}
> I2CDRB = 0xFE; // manufacturer id
> while ((I2CTCTL & I2CSTP) == I2CSTP);
>
Ok, since nobody answered let me just mention what I've observed but I
am using SPI a lot, no I2C in many years. So I am not an expert on this.
Anyhow, I2C devices seem to hang at times and what people did was this:
a. Time-out, just like you are planning to do. IIRC a few tens of msec.
b. Issueing some stop commands.
c. Holding SCK and SDA low for a while, hoping that this will pull the
recalcitrant device out of the mud.
--
Regards, Joerg
http://www.analogconsultants.com/
------------------------------------
(You need to be a member of msp430 -- send a blank email to msp430-subscribe@yahoogroups.com )
> Hello forumers, I am using MSP430F1610 to communicate with i2c/SMBus
> devices. It runs OK when the the i2c devices are working fine. But if
> the device is not working/defective/not responding, my code hangs. How
> do you know that there is error in i2c communication? As for now, i
> place a counter to exit if the device is not responding after some
> counts.
>
> while (I2CDCTL & I2CBUSY);
> I2CNDAT = 0x01;
> I2CSA = 0x18; U0CTL |= MST;
> I2CTCTL |= I2CSTT+I2CSTP+I2CTRX; // write
> while ((I2CIFG & TXRDYIFG) == 0x0) // it hangs here if no counter
> {cnt++; if (cnt > 5000){tj_id = 0x30; reak;}}
> I2CDRB = 0xFE; // manufacturer id
> while ((I2CTCTL & I2CSTP) == I2CSTP);
>
Ok, since nobody answered let me just mention what I've observed but I
am using SPI a lot, no I2C in many years. So I am not an expert on this.
Anyhow, I2C devices seem to hang at times and what people did was this:
a. Time-out, just like you are planning to do. IIRC a few tens of msec.
b. Issueing some stop commands.
c. Holding SCK and SDA low for a while, hoping that this will pull the
recalcitrant device out of the mud.
--
Regards, Joerg
http://www.analogconsultants.com/
------------------------------------
(You need to be a member of msp430 -- send a blank email to msp430-subscribe@yahoogroups.com )
Re: SMBus or i2c error - Joerg - Aug 21 18:51:39 2008
magzky02 wrote:
> Hello forumers, I am using MSP430F1610 to communicate with i2c/SMBus
> devices. It runs OK when the the i2c devices are working fine. But if
> the device is not working/defective/not responding, my code hangs. How
> do you know that there is error in i2c communication? As for now, i
> place a counter to exit if the device is not responding after some
> counts.
Just one more remark. It may be good to find out why this hang-up
happens. Connect a scope to the I2C lines, look for overshoots,
undershoots, ringing, spikes, EMI, the usual. Try to find out if some
big load is being switched when it happens or if a cell phone is being
turned on. Maybe a little AC termination is needed on those lines.
--
Regards, Joerg
http://www.analogconsultants.com/
------------------------------------
(You need to be a member of msp430 -- send a blank email to msp430-subscribe@yahoogroups.com )
> Hello forumers, I am using MSP430F1610 to communicate with i2c/SMBus
> devices. It runs OK when the the i2c devices are working fine. But if
> the device is not working/defective/not responding, my code hangs. How
> do you know that there is error in i2c communication? As for now, i
> place a counter to exit if the device is not responding after some
> counts.
Just one more remark. It may be good to find out why this hang-up
happens. Connect a scope to the I2C lines, look for overshoots,
undershoots, ringing, spikes, EMI, the usual. Try to find out if some
big load is being switched when it happens or if a cell phone is being
turned on. Maybe a little AC termination is needed on those lines.
--
Regards, Joerg
http://www.analogconsultants.com/
------------------------------------
(You need to be a member of msp430 -- send a blank email to msp430-subscribe@yahoogroups.com )
Re: Re: SMBus or i2c error - mago Umandam - Aug 22 8:32:28 2008
Thanks Joerg. Seems the best way is to time it out. Because my aplication i=
s a tester, it must be able to handle cases like this where the i2c slave d=
evice doesnt respond.
=A0
regards,
mago
--- On Fri, 8/22/08, Joerg wrote:
From: Joerg
Subject: [msp430] Re: SMBus or i2c error
To: m...@yahoogroups.com
Date: Friday, August 22, 2008, 6:30 AM
magzky02 wrote:
> Hello forumers, I am using MSP430F1610 to communicate with i2c/SMBus=20
> devices. It runs OK when the the i2c devices are working fine. But if=20
> the device is not working/defective/ not responding, my code hangs. How=20
> do you know that there is error in i2c communication? As for now, i=20
> place a counter to exit if the device is not responding after some=20
> counts.=20
>=20
> while (I2CDCTL & I2CBUSY);=20
> I2CNDAT =3D 0x01;
> I2CSA =3D 0x18; U0CTL |=3D MST;=20
> I2CTCTL |=3D I2CSTT+I2CSTP+ I2CTRX; // write
> while ((I2CIFG & TXRDYIFG) =3D=3D 0x0) // it hangs here if no counter
> {cnt++; if (cnt > 5000){tj_id =3D 0x30; reak;}}=20
> I2CDRB =3D 0xFE; // manufacturer id=20
> while ((I2CTCTL & I2CSTP) =3D=3D I2CSTP);=20
>=20
Ok, since nobody answered let me just mention what I've observed but I=20
am using SPI a lot, no I2C in many years. So I am not an expert on this.=20
Anyhow, I2C devices seem to hang at times and what people did was this:
a. Time-out, just like you are planning to do. IIRC a few tens of msec.
b. Issueing some stop commands.
c. Holding SCK and SDA low for a while, hoping that this will pull the=20
recalcitrant device out of the mud.
--=20
Regards, Joerg
http://www.analogco nsultants. com/
=20
=20=20=20=20=20=20
[Non-text portions of this message have been removed]
------------------------------------
(You need to be a member of msp430 -- send a blank email to msp430-subscribe@yahoogroups.com )
s a tester, it must be able to handle cases like this where the i2c slave d=
evice doesnt respond.
=A0
regards,
mago
--- On Fri, 8/22/08, Joerg
From: Joerg
Subject: [msp430] Re: SMBus or i2c error
To: m...@yahoogroups.com
Date: Friday, August 22, 2008, 6:30 AM
magzky02 wrote:
> Hello forumers, I am using MSP430F1610 to communicate with i2c/SMBus=20
> devices. It runs OK when the the i2c devices are working fine. But if=20
> the device is not working/defective/ not responding, my code hangs. How=20
> do you know that there is error in i2c communication? As for now, i=20
> place a counter to exit if the device is not responding after some=20
> counts.=20
>=20
> while (I2CDCTL & I2CBUSY);=20
> I2CNDAT =3D 0x01;
> I2CSA =3D 0x18; U0CTL |=3D MST;=20
> I2CTCTL |=3D I2CSTT+I2CSTP+ I2CTRX; // write
> while ((I2CIFG & TXRDYIFG) =3D=3D 0x0) // it hangs here if no counter
> {cnt++; if (cnt > 5000){tj_id =3D 0x30; reak;}}=20
> I2CDRB =3D 0xFE; // manufacturer id=20
> while ((I2CTCTL & I2CSTP) =3D=3D I2CSTP);=20
>=20
Ok, since nobody answered let me just mention what I've observed but I=20
am using SPI a lot, no I2C in many years. So I am not an expert on this.=20
Anyhow, I2C devices seem to hang at times and what people did was this:
a. Time-out, just like you are planning to do. IIRC a few tens of msec.
b. Issueing some stop commands.
c. Holding SCK and SDA low for a while, hoping that this will pull the=20
recalcitrant device out of the mud.
--=20
Regards, Joerg
http://www.analogco nsultants. com/
=20
=20=20=20=20=20=20
[Non-text portions of this message have been removed]
------------------------------------
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