FPin question
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Posts: 46,084
Hi Stampers,
I would like to use the flow control on the basic stamp 2.
I use the following command:
Serin 9\10, 384, [noparse][[/noparse]Data]
When the stamp reaches this statement, the pin 10 should be
Low to start the transmission, but in my Stamp it is High.
If I change the BaudMode to 16780 (ie. polarity change)
the FPin should be High to start. It is true.
As the manual says the polarity bit determines this behaviour
but it seems that it is not true, it is always High when
the communication can start. (After the Serin command
FPin changes to Low in both cases)
Is it bug or feature ?
Any help would be appreciated
Thanks in advance
Liszli
I would like to use the flow control on the basic stamp 2.
I use the following command:
Serin 9\10, 384, [noparse][[/noparse]Data]
When the stamp reaches this statement, the pin 10 should be
Low to start the transmission, but in my Stamp it is High.
If I change the BaudMode to 16780 (ie. polarity change)
the FPin should be High to start. It is true.
As the manual says the polarity bit determines this behaviour
but it seems that it is not true, it is always High when
the communication can start. (After the Serin command
FPin changes to Low in both cases)
Is it bug or feature ?
Any help would be appreciated
Thanks in advance
Liszli
Comments
Are you sure some external circuit is not holding the pin high?
In my experience it works as advertised in the Stamp manual. I have
a write-up about it at:
http://www.emesystems.com/BS2rs232.htm#serialflow
-- regards,
Tracy Allen
electronically monitored ecosystems
mailto:tracy@e...
http://www.emesystems.com
>Hi Stampers,
>
>I would like to use the flow control on the basic stamp 2.
>I use the following command:
>Serin 9\10, 384, [noparse][[/noparse]Data]
>
>When the stamp reaches this statement, the pin 10 should be
>Low to start the transmission, but in my Stamp it is High.
>If I change the BaudMode to 16780 (ie. polarity change)
>the FPin should be High to start. It is true.
>As the manual says the polarity bit determines this behaviour
>but it seems that it is not true, it is always High when
>the communication can start. (After the Serin command
>FPin changes to Low in both cases)
>
>Is it bug or feature ?
>
>Any help would be appreciated
>Thanks in advance
>Liszli
>
>
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I might have missed something, but two points:
1. Is it possible that the other device might be holding Pin 10 high?
2. Have you a statement earlier in the code that is forcing the pin high.
I sometimes get mixed up with pins and end up with a smoke-filled lab. In
fact once I found I was using the same stamp pin to drive a serial LCD and
input serial data from a PC - it worked for a week and then the pin died....
Regards,
Tony Wells
Original Message
From: "ilzsil" <liszli@f...>
To: <basicstamps@yahoogroups.com>
Sent: Tuesday, January 29, 2002 3:15 PM
Subject: [noparse][[/noparse]basicstamps] FPin question
> Hi Stampers,
>
> I would like to use the flow control on the basic stamp 2.
> I use the following command:
> Serin 9\10, 384, [noparse][[/noparse]Data]
>
> When the stamp reaches this statement, the pin 10 should be
> Low to start the transmission, but in my Stamp it is High.
> If I change the BaudMode to 16780 (ie. polarity change)
> the FPin should be High to start. It is true.
> As the manual says the polarity bit determines this behaviour
> but it seems that it is not true, it is always High when
> the communication can start. (After the Serin command
> FPin changes to Low in both cases)
>
> Is it bug or feature ?
>
> Any help would be appreciated
> Thanks in advance
> Liszli
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
First of all this problem has been solved.
Resolution:
(The pin 10 has not been hold to any state not from inside
neither from outside).
The pin 9 was connected to a PIC16F627. The stamp receives
the data from this pin therefore it is an output on the PIC.
The power supply of the stamp and the PIC is independent from
each other. When I power on the PIC first it initializes
this pin to an output and makes it high, but since the
stamp power supply is switched on later it loads the PIC
and this pin goes low. (Probably a closed circuit?)
And after having power on the stamp this pin state determines
the Fpin's state (I don't know why but it seems to me)
In normal circumstances the Receive pin (RPin) is high
(on TTL levels) when idle but in my case this wasn't right.
Probably the firmware in the stamp checks the RPin and then
inverts the polarity and then sets the FPin.
After I connected serially an 470 ohms resistor between
pin 9 and the PIC everything is fine since at bootup the PIC's
output isn't loaded too heavily and its state is set correctly.
Thanks for the replies
Liszli
--- In basicstamps@y..., <tony.wells@a...> wrote:
> Hi Liszli,
>
> I might have missed something, but two points:
>
> 1. Is it possible that the other device might be holding Pin 10
high?
> 2. Have you a statement earlier in the code that is forcing the pin
high.
> I sometimes get mixed up with pins and end up with a smoke-filled
lab. In
> fact once I found I was using the same stamp pin to drive a serial
LCD and
> input serial data from a PC - it worked for a week and then the pin
died....
>
> Regards,
>
> Tony Wells
Good, I'm glad you got it sorted. At least one other poster has recommended
a 1k resistor between these types of devices.
I always mean to get round to it, and always manage to forget...
Regards,
Tony
Original Message
From: "ilzsil" <liszli@f...>
To: <basicstamps@yahoogroups.com>
Sent: Wednesday, January 30, 2002 3:25 PM
Subject: [noparse][[/noparse]basicstamps] Re: FPin question
> Hi Tony,
>
> First of all this problem has been solved.
> Resolution:
> (The pin 10 has not been hold to any state not from inside
> neither from outside).
> The pin 9 was connected to a PIC16F627. The stamp receives
> the data from this pin therefore it is an output on the PIC.
> The power supply of the stamp and the PIC is independent from
> each other. When I power on the PIC first it initializes
> this pin to an output and makes it high, but since the
> stamp power supply is switched on later it loads the PIC
> and this pin goes low. (Probably a closed circuit?)
> And after having power on the stamp this pin state determines
> the Fpin's state (I don't know why but it seems to me)
> In normal circumstances the Receive pin (RPin) is high
> (on TTL levels) when idle but in my case this wasn't right.
> Probably the firmware in the stamp checks the RPin and then
> inverts the polarity and then sets the FPin.
> After I connected serially an 470 ohms resistor between
> pin 9 and the PIC everything is fine since at bootup the PIC's
> output isn't loaded too heavily and its state is set correctly.
>
> Thanks for the replies
> Liszli
>
> --- In basicstamps@y..., <tony.wells@a...> wrote:
> > Hi Liszli,
> >
> > I might have missed something, but two points:
> >
> > 1. Is it possible that the other device might be holding Pin 10
> high?
> > 2. Have you a statement earlier in the code that is forcing the pin
> high.
> > I sometimes get mixed up with pins and end up with a smoke-filled
> lab. In
> > fact once I found I was using the same stamp pin to drive a serial
> LCD and
> > input serial data from a PC - it worked for a week and then the pin
> died....
> >
> > Regards,
> >
> > Tony Wells
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
device(Stamp) to be powered when your outside PIC sets the Stamp pin high
while Stamp Vcc is at float. All kinds of weird things can happen with this
scenario. Sounds like your fix will take care of all aspects of this, along
with functionality.
Chris
Chris
--
First of all this problem has been solved.
Resolution:
(The pin 10 has not been hold to any state not from inside
neither from outside).
The pin 9 was connected to a PIC16F627. The stamp receives
the data from this pin therefore it is an output on the PIC.
The power supply of the stamp and the PIC is independent from
each other. When I power on the PIC first it initializes
this pin to an output and makes it high, but since the
stamp power supply is switched on later it loads the PIC
and this pin goes low. (Probably a closed circuit?)
And after having power on the stamp this pin state determines
the Fpin's state (I don't know why but it seems to me)
In normal circumstances the Receive pin (RPin) is high
(on TTL levels) when idle but in my case this wasn't right.
Probably the firmware in the stamp checks the RPin and then
inverts the polarity and then sets the FPin.
After I connected serially an 470 ohms resistor between
pin 9 and the PIC everything is fine since at bootup the PIC's
output isn't loaded too heavily and its state is set correctly.
Thanks for the replies
Liszli