AVR-Chat

Hello Friends,
 
Good Morning!...
 
I need help/suggestion from you!
 
Actually I have a device which communicates with microcontroller using the 
serial communication. but sometimes this device stops communicating.In this case 
, this device needs VCC reset( POWER RESET)..So what i want is to reset this 
device from microcontroller  whenever it stops communicating ( basically 
disconnecting the VCC power of this device by turning on some output pin of 
microcontroller  and after 1 or 2 seconds again connecting it)...I don't want to 
use relay logic..so any suggestions regarding the hardware interfacing circuit 
between microcontroller and this device which stopd communicating and need Power 
reset. Current requirement of this device is below 600 mA. and voltage VCC is 
same as microcontroller ( +5V).
 
Thanks a lot!,
 
Best Regards,
Kaps


      

[Non-text portions of this message have been removed]

You could use a P channel FET at that current level. An on resistance  
of 0.1 ohms will give you a voltage drop of 60mV at 600ma and a  
forward gate voltage of 5V should get a "logic level" device well  
turned on.

Jim

On Sep 2, 2010, at 8:05 PM, AMIT KAPOOR wrote:

> Hello Friends,
>
> Good Morning!...
>
> I need help/suggestion from you!
>
> Actually I have a device which communicates with microcontroller  
> using the
> serial communication. but sometimes this device stops  
> communicating.In this case
> , this device needs VCC reset( POWER RESET)..So what i want is to  
> reset this
> device from microcontroller  whenever it stops communicating  
> ( basically
> disconnecting the VCC power of this device by turning on some output  
> pin of
> microcontroller  and after 1 or 2 seconds again connecting it)...I  
> don't want to
> use relay logic..so any suggestions regarding the hardware  
> interfacing circuit
> between microcontroller and this device which stopd communicating  
> and need Power
> reset. Current requirement of this device is below 600 mA. and  
> voltage VCC is
> same as microcontroller ( +5V).
>
> Thanks a lot!,
>
> Best Regards,
> Kaps
>
> [Non-text portions of this message have been removed]
>
>
> 



[Non-text portions of this message have been removed]

Hello :)

You can use the cheap FET, may be some thing like BSS138, but with P-chanell (to open FET with a low logical level sygnal). As I remember it can commutate about a half of 1A.

Eugene

Hi there,
 
Is the reason for stopping a failure in the code somewhere?
 
What about enabling the watchdog and if your code crashes and stops updating
this, it will do a reset for you and your code will start again as if power
off and on. This will be much simpler than doing the external switch.
 
If this works, then you need to dig into your code to figure out why it
stops communicating as it sounds very much like a bug in their somewhere?
 
If your code is still executing (as you are able to toggle an IO pin) then
you can simply enable the watchdog from within your code and then enter a
while loop until it times out and resets your device. Again, no need for
external hardware.
 
Regards
Dave.

From: AVR-Chat@yahoogroups.com [mailto:AVR-Chat@yahoogroups.com] On Behalf
Of AMIT KAPOOR
Sent: 03 September 2010 10:06
To: AVR-Chat@yahoogroups.com
Subject: [AVR-Chat] Power reset (VCC) of some device from MICROCONTROLLER
OUTPUT PIN without using relay
 
  
Hello Friends,
 
Good Morning!...
 
I need help/suggestion from you!
 
Actually I have a device which communicates with microcontroller using the 
serial communication. but sometimes this device stops communicating.In this
case 
, this device needs VCC reset( POWER RESET)..So what i want is to reset this

device from microcontroller  whenever it stops communicating ( basically 
disconnecting the VCC power of this device by turning on some output pin of 
microcontroller  and after 1 or 2 seconds again connecting it)...I don't
want to 
use relay logic..so any suggestions regarding the hardware interfacing
circuit 
between microcontroller and this device which stopd communicating and need
Power 
reset. Current requirement of this device is below 600 mA. and voltage VCC
is 
same as microcontroller ( +5V).
 
Thanks a lot!,
 
Best Regards,
Kaps




[Non-text portions of this message have been removed]

Sometimes there is no other way, but we don't know the project details

Hello Dave,

Thanks for the reply.

Actually the problem is not on the PIC side . The problem is on the other device 
with which PIC is communicating. So i have to reset( Power) the other device and 
not the PIC. basically there is predefined protocol( from this device comany) to 
communicate with this device but sometimes this device hangs and stops 
responding. There is no option other than to hard reset it..So i need something 
to hard reset the VCC of this device. I hope i am clear.

Is there some IC which can source current of around 600 ma( 1 Amp will be on 
safe side!) and can be turned on/off from PIC pin. That would be perfect!...Any 
Suggestions??

Thanks 
Kaps






________________________________

From: Dave McLaughlin <dave_mclaughlin@nerdshack.com>
To: AVR-Chat@yahoogroups.com
Sent: Fri, September 3, 2010 1:01:16 PM
Subject: RE: [AVR-Chat] Power reset (VCC) of some device from MICROCONTROLLER 
OUTPUT PIN without using relay

  
Hi there,

Is the reason for stopping a failure in the code somewhere?

What about enabling the watchdog and if your code crashes and stops updating
this, it will do a reset for you and your code will start again as if power
off and on. This will be much simpler than doing the external switch.

If this works, then you need to dig into your code to figure out why it
stops communicating as it sounds very much like a bug in their somewhere?

If your code is still executing (as you are able to toggle an IO pin) then
you can simply enable the watchdog from within your code and then enter a
while loop until it times out and resets your device. Again, no need for
external hardware.

Regards
Dave.

From: AVR-Chat@yahoogroups.com [mailto:AVR-Chat@yahoogroups.com] On Behalf
Of AMIT KAPOOR
Sent: 03 September 2010 10:06
To: AVR-Chat@yahoogroups.com
Subject: [AVR-Chat] Power reset (VCC) of some device from MICROCONTROLLER
OUTPUT PIN without using relay


Hello Friends,

Good Morning!...

I need help/suggestion from you!

Actually I have a device which communicates with microcontroller using the 
serial communication. but sometimes this device stops communicating.In this
case 
, this device needs VCC reset( POWER RESET)..So what i want is to reset this

device from microcontroller whenever it stops communicating ( basically 
disconnecting the VCC power of this device by turning on some output pin of 
microcontroller and after 1 or 2 seconds again connecting it)...I don't
want to 
use relay logic..so any suggestions regarding the hardware interfacing
circuit 
between microcontroller and this device which stopd communicating and need
Power 
reset. Current requirement of this device is below 600 mA. and voltage VCC
is 
same as microcontroller ( +5V).

Thanks a lot!,

Best Regards,
Kaps

[Non-text portions of this message have been removed]





      

[Non-text portions of this message have been removed]

There is ULN200x - eight  channels, 600mA max each (500 mA continuous current), but why don't you want to use FET? it's easier you ever think ;)

Or...

   You can find out why your other side of the communications channel 
isn't working properly and fix the problem instead of addressing the 
symptoms, which is pretty much guaranteed to fail you when you need it most.

Just a thought,
DLC

evgenii sorokin wrote:
> Hello :)
> 
> You can use the cheap FET, may be some thing like BSS138, but with P-chanell (to open FET with a low logical level sygnal). As I remember it can commutate about a half of 1A.
> 
> Eugene
> 
> 
> ------------------------------------
> 
> Yahoo! Groups Links
> 
> 
> 

-- 
-------------------------------------------------
Dennis Clark          TTT Enterprises
www.techtoystoday.com
-------------------------------------------------

On Sep 2, 2010, at 10:13 PM, AMIT KAPOOR wrote:

>
> Hello Dave,
>
> Thanks for the reply.
>
> Actually the problem is not on the PIC side . The problem is on the  
> other device
> with which PIC is communicating. So i have to reset( Power) the  
> other device and
> not the PIC. basically there is predefined protocol( from this  
> device comany) to
> communicate with this device but sometimes this device hangs and stops
> responding. There is no option other than to hard reset it..So i  
> need something
> to hard reset the VCC of this device. I hope i am clear.
>
> Is there some IC which can source current of around 600 ma( 1 Amp  
> will be on
> safe side!) and can be turned on/off from PIC pin. That would be  
> perfect!...Any
> Suggestions??
>
> Thanks
> Kaps
>
> ________________________________
>
Sure - use the P channel FET I mentioned earlier. Control it with your  
micro. No special IC needed.

Jim Wagner
Oregon Research Electronics



[Non-text portions of this message have been removed]

Ah OK. Now you’re starting to make sense of where the fault is.
 
As someone else already suggested, shouldn’t you investigate with the original supplier of the board you are talking to and find out why it hangs? 
 
Can you replicate the failure? Surely powering off this board is very drastic and are you sure that there are no other consequences of doing so? Like for instance, what is it connected to? Is powering on and off going to cause other issues later on.
 
Better to fix the problem than try to work around it if at all possible.
 
PS.. If you want to see how to use a FET to switch VCC on or off, check out the circuits for the FT232RL from FTDI. They use this very technique to power up external devices after the USB driver has negotiated the link with the USB host controller in the PC. You can control this FET from your micro easily.
 
Regards
Dave…

From: AVR-Chat@yahoogroups.com [mailto:AVR-Chat@yahoogroups.com] On Behalf Of AMIT KAPOOR
Sent: 03 September 2010 12:14
To: AVR-Chat@yahoogroups.com
Subject: Re: [AVR-Chat] Power reset (VCC) of some device from MICROCONTROLLER OUTPUT PIN without using relay
 
  

Hello Dave,

Thanks for the reply.

Actually the problem is not on the PIC side . The problem is on the other device 
with which PIC is communicating. So i have to reset( Power) the other device and 
not the PIC. basically there is predefined protocol( from this device comany) to 
communicate with this device but sometimes this device hangs and stops 
responding. There is no option other than to hard reset it..So i need something 
to hard reset the VCC of this device. I hope i am clear.

Is there some IC which can source current of around 600 ma( 1 Amp will be on 
safe side!) and can be turned on/off from PIC pin. That would be perfect!...Any 
Suggestions??

Thanks 
Kaps




[Non-text portions of this message have been removed]

Hello Evgenii ,

Yes you are right! but actually  BSS138 which you mentioned doesn't have DIP 
package  and i want to test on the breadboard ...I have L293 DC motor driver 
chip with me now...can i use this chip for my purpose i.e. connecting the output 
pin of L293 to the Device VCC of my device and reseting it (when required ) from 
the microcontroller output pin ?....

Regards,
Amit





________________________________

From: evgenii sorokin <escorrespondence@mail.ru>
To: AVR-Chat@yahoogroups.com
Sent: Fri, September 3, 2010 2:21:15 PM
Subject: Re[2]: [AVR-Chat] Power reset (VCC) of some device from MICROCONTROLLER 
OUTPUT PIN without using relay

There is ULN200x - eight  channels, 600mA max each (500 mA continuous current), 
but why don't you want to use FET? it's easier you ever think ;)


------------------------------------

Yahoo! Groups Links




      

[Non-text portions of this message have been removed]

BSS138  is packed in sot23, so if you want to test it, you  can solder the pins (wires) as you need :), but don't forget that this is n-channel FET, you must open it with logical "0".

If you are "worried" with this, find the nearest p-channel fet and use it the same way


Eugene

On Sep 2, 2010, at 10:51 PM, AMIT KAPOOR wrote:

> Hello Evgenii ,
> 
> Yes you are right! but actually  BSS138 which you mentioned doesn't have DIP 
> package  and i want to test on the breadboard ...I have L293 DC motor driver 
> chip with me now...can i use this chip for my purpose i.e. connecting the output 
> pin of L293 to the Device VCC of my device and reseting it (when required ) from 
> the microcontroller output pin ?....
> 
The L293 isn't a good choice, it has at least an NPN darlington transistor as a source driver so it is going to be dropping 1.5V or so.  Meaning you will get 3.5V to the circuit (or less).
>  
> 

Clark Martin
Redwood City, CA, USA
Macintosh / Internet Consulting

"I'm a designated driver on the Information Super Highway"



[Non-text portions of this message have been removed]

Hi Amit,

Why would you need a device in a DIP package? A FET only has three leads. If
you need to test it on a breadboard, use something in a TO-92 or TO-220
package.

What is the failing device, anyway, and where did you get it?

I swear that half of electrical engineering these days is knowing and being
able to find the components most appropriate to your needs.


Zack

On Fri, Sep 3, 2010 at 12:51 AM, AMIT KAPOOR <kaps_iit@yahoo.com> wrote:

>
>
> Hello Evgenii ,
>
> Yes you are right! but actually  BSS138 which you mentioned doesn't have
> DIP
> package  and i want to test on the breadboard ...I have L293 DC motor
> driver
> chip with me now...can i use this chip for my purpose i.e. connecting the
> output
> pin of L293 to the Device VCC of my device and reseting it (when required )
> from
> the microcontroller output pin ?....
>
> Regards,
> Amit
>
> ________________________________
> From: evgenii sorokin <escorrespondence@mail.ru<escorrespondence%40mail.ru>
> >
>
> To: AVR-Chat@yahoogroups.com <AVR-Chat%40yahoogroups.com>
> Sent: Fri, September 3, 2010 2:21:15 PM
> Subject: Re[2]: [AVR-Chat] Power reset (VCC) of some device from
> MICROCONTROLLER
> OUTPUT PIN without using relay
>
> There is ULN200x - eight  channels, 600mA max each (500 mA continuous
> current),
> but why don't you want to use FET? it's easier you ever think ;)
>
> ------------------------------------
>
> Yahoo! Groups Links
>
> [Non-text portions of this message have been removed]
>
>  
>


[Non-text portions of this message have been removed]