--- In jallist@yahoogroups.com, Eur van Andel <eur@f...> wrote:
> This is very much worth further discussion.

Greetings,

OK, here is a "string" of 4 diodes. Each diode has 1 resistor and 1
capacitor connected in parallel with it.

Now, let me see if I can find a description of why those extra
components are there...

Here is one, from Radio Handbook, William Orr, 23rd Ed. Chapter 19:

"Series diode operation is commonly used when the peak-inverse voltage
of the source is greater than the max PIV rating of a single diode.
For proper operation, it is important that the PIV be equally divided
among the individual diodes. If it is not, one or more of the diodes
int the stack (string) will be subjected to a PIV greater than its max
rating, and as a result may be destroyed... most failures will result
in a short, which will lead to a "domino effect" which will destroy
the remaining diodes..."

They suggest a formula, which claims to achieve a 10-percent voltage
balance, or better:

R = PIV / ( 2 * Max Reverse Current )

The capacitors are to protect the diodes from voltage transients. They
suggest a value of 100 times the capacitance of the diode junction.

           ___                 ___               ___            ___
      .---|___|---.      .----|___|----.    .---|___|--.    .--|___|-.
      |           |      |             |    |          |    |        |
  ----o-o-->|---o-o------o---o->|---o--o----o-o-->|--o-o----o-o->|--o---
        |       |            |      |         |      |        |     |
        |   ||  |            |  ||  |         |   || |        |  || |
        '---||--'            '--||--'         '---||-'        '--||-'
            ||                  ||                ||             ||

(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)


William

Here: http://oase.uci.kun.nl/~mientki/pic/projects/pic_ir.html they
show a schema for a IR-sender, which can send using the USART of the
PIC16f628. I'm figuring out how to do that.

Below the diagram/schema of the IR-sender the say this:
-------------
The most elegant circuit.

Minimum of software requirements, just set the special PWM output to
the desired modulation frequency and just send the characters to the
USART.

The limitation of this circuit lies in the fact that only valid 8 or 9
bit RS232 compatible bytes can be sent (1 start bit, 1 or 2 stop bits).
-------------

Now I'm wondering how I can set the "special PWM output to the desired
modulation frequency". So lets say I want to test using 36KHz and
40Khz, how can I set this. And how can I send data than. (All using JAL).

Thanx a lot!!


--- In jallist@yahoogroups.com, "diederickhuijbers" <d.huijbers@a...>
wrote:
> No sorry, that's why I want to do it using JAL..
> Thanx for your reply though!
>
> --- In jallist@yahoogroups.com, "upand_at_them" <upand_at_them@y...>
> wrote:
> > Do you know assembly?  If so, here's a tutorial for IR:
> > http://www.lpilsley.uklinux.net/picprog/pic_tutorial5.htm
> >
> > Mike

No sorry, that's why I want to do it using JAL..
Thanx for your reply though!

--- In jallist@yahoogroups.com, "upand_at_them" <upand_at_them@y...>
wrote:
> Do you know assembly?  If so, here's a tutorial for IR:
> http://www.lpilsley.uklinux.net/picprog/pic_tutorial5.htm
>
> Mike

Do you know assembly?  If so, here's a tutorial for IR:
http://www.lpilsley.uklinux.net/picprog/pic_tutorial5.htm

Mike

Hi there!

Thanx for your replys. But maybe I should've written my message a bit
more clear. I'm really new to al these electronics stuff, and I just
want to start testing with a IR-sender (later a receiver). But I
really don't know how to accomplish this using JAL and the PIC16f628.

I read somewhere I should use the build in PWM. But what will this PWM
  do? And how does that work? Because if i'm correct you can just put
the PWM 'on' using assembler, that's all? And how could I send data
which I later can receive with an IR-receiver?

Thanx a lot in advance!
Greetings

--- In jallist@yahoogroups.com, Chris Ellis <cellis@i...> wrote:
> Hi
>
> The data sent via a tv remote control is modulated at 38 KHz .  This
> means that the led is at 38khz then the pic output wil  turn the pulse
> on and off.  This should be ok to impletment in pic code.  However the
> other problem is that tv remote controls data is encoded in a format
> called manchester encoding.  I have written a libary to to the
> encoding,  turns an 8 bit byte into two 8 bit bytes because of the way
> the encoding work.  However it is the way to reliably send data over RF
> or IR.  you can find the info at my site
>
www.chrisellis.me.uk/index.php?option=com_content&task=view&id=7&Itemid=16
>
> To modulate the Ir you could use an external oscillator :
>
> Chris
>
>
> diederickhuijbers wrote:
>
> > Hi there,
> >
> > For a project I need to use IR communication. I just wanted to start
> > trying to build a simple transmitter. Maybe it is possible to create a
> > simple transmitter for my philips t.v.?
> >
> > I created this circuit:
> > http://oase.uci.kun.nl/~mientki/pic/projects/ir_transmit2.gif
> > <http://oase.uci.kun.nl/%7Emientki/pic/projects/ir_transmit2.gif>
> > But I'm only using one IR LED and a 100 ohm resistor.
> >
> > Now after reading a lot of information I think I have to use the build
> > in PWM functionality of the PIC16f628.
> >
> > Does anyone has some JAL code how to accomplish a simple transmitter?
> > And maybe an example of how I can test it (maybe with my
television?) ?
> >
> > Thanx in advance!
> >
> >
> >
> >
------------------------------------------------------------------------
> > *Yahoo! Groups Links*
> >
> >     * To visit your group on the web, go to:
> >       http://groups.yahoo.com/group/jallist/
> >
> >     * To unsubscribe from this group, send an email to:
> >       jallist-unsubscribe@yahoogroups.com
> >       <mailto:jallist-unsubscribe@yahoogroups.com?subject=Unsubscribe>
> >
> >     * Your use of Yahoo! Groups is subject to the Yahoo! Terms of
> >       Service <http://docs.yahoo.com/info/terms/>.
> >
> >
>
>
>
>
> [Non-text portions of this message have been removed]

> The data sent via a tv remote control is modulated at 38 KHz .

Make that 'can be'. In fact all frequencies from 30 up to 60 kHz are
used, and on top of that there are a few more rare remote control
techniques that use just pulses, no carrier.

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: www.voti.nl/hvu

>To modulate the Ir you could use an external oscillator :
>
>
The nice thing of the suggested schematic is that the 38 kHz modulation
is done by the hardware PWM module ;-)

Stef

>
>

Hi

The data sent via a tv remote control is modulated at 38 KHz .  This
means that the led is at 38khz then the pic output wil  turn the pulse
on and off.  This should be ok to impletment in pic code.  However the
other problem is that tv remote controls data is encoded in a format
called manchester encoding.  I have written a libary to to the
encoding,  turns an 8 bit byte into two 8 bit bytes because of the way
the encoding work.  However it is the way to reliably send data over RF
or IR.  you can find the info at my site
www.chrisellis.me.uk/index.php?option=com_content&task=view&id=7&Itemid=16

To modulate the Ir you could use an external oscillator :

Chris


diederickhuijbers wrote:

> Hi there,
>
> For a project I need to use IR communication. I just wanted to start
> trying to build a simple transmitter. Maybe it is possible to create a
> simple transmitter for my philips t.v.?
>
> I created this circuit:
> http://oase.uci.kun.nl/~mientki/pic/projects/ir_transmit2.gif
> <http://oase.uci.kun.nl/%7Emientki/pic/projects/ir_transmit2.gif>
> But I'm only using one IR LED and a 100 ohm resistor.
>
> Now after reading a lot of information I think I have to use the build
> in PWM functionality of the PIC16f628.
>
> Does anyone has some JAL code how to accomplish a simple transmitter?
> And maybe an example of how I can test it (maybe with my television?) ?
>
> Thanx in advance!
>
>
>
> ------------------------------------------------------------------------
> *Yahoo! Groups Links*
>
>     * To visit your group on the web, go to:
>       http://groups.yahoo.com/group/jallist/
>
>     * To unsubscribe from this group, send an email to:
>       jallist-unsubscribe@yahoogroups.com
>       <mailto:jallist-unsubscribe@yahoogroups.com?subject=Unsubscribe>
>
>     * Your use of Yahoo! Groups is subject to the Yahoo! Terms of
>       Service <http://docs.yahoo.com/info/terms/>.
>
>




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

Hi there,

For a project I need to use IR communication. I just wanted to start
trying to build a simple transmitter. Maybe it is possible to create a
simple transmitter for my philips t.v.?

I created this circuit:
http://oase.uci.kun.nl/~mientki/pic/projects/ir_transmit2.gif
But I'm only using one IR LED and a 100 ohm resistor.

Now after reading a lot of information I think I have to use the build
in PWM functionality of the PIC16f628.

Does anyone has some JAL code how to accomplish a simple transmitter?
And maybe an example of how I can test it (maybe with my television?) ?

Thanx in advance!

sent
xxxxxxxxxx

Your message entitled

     [EE] NTSC tuners

was successfully received by the Piclist mailing list.

xxxxxxxxxxxxxxx

To: Microcontroller discussion list - Public. <piclist@...>
Subject: [EE] NTSC tuners
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit

.....
Guys, help me.

  >From some obscure reasons I can't ask questions to the piclist, I can
only answer. Even I change an existing subject topic does not work.

I need to found urgent an european producer of NTSC tuners. Funny
isn't it ? Any help?

thx,
Vasile

xxxxxxxxxxxxxx

original






Vasile Surducan wrote:

>Guys, help me.
>
>>From some obscure reasons I can't ask questions to the piclist, I can
>only answer. Even I change an existing subject topic does not work.
>
>I need to found urgent an european producer of NTSC tuners. Funny
>isn't it ? Any help?
>
>thx,
>Vasile
>
>

On 02 Jun, 2005, at 12:59, Vasile Surducan wrote:

> If the stepper does not have a heavy load even an 1N4148 my work
> (200V), but often will be burned because of it's small direct current
> (about 100mA, maxim 200 mA)
Amen! The L298 will fry too.


ir EE van Andel eur@... www.fiwihex.nl
Fiwihex B.V. Wierdensestraat 74, NL7604BK Almelo, Netherlands
tel+31-546-491106 fax+31-546-491107

On Thursday 02 June 2005 11:02, Vasile Surducan wrote:
> Guys, help me.
>
> From some obscure reasons I can't ask questions to the piclist, I can
> only answer. Even I change an existing subject topic does not work.
>
> I need to found urgent an european producer of NTSC tuners. Funny
> isn't it ? Any help?
>
> thx,
> Vasile

philips or thompson (taken from /usr/src/linux/drivers/media/video)

Philips NTSC (FI1236,FM1236 and compatibles)
Philips NTSC_M (MK2)
Philips NTSC MK3 (FM1236MK3 or FM1236/F)
Thomson DDT 7610 ATSC/NTSC)
Philips FQ1286

regards
--
Simon

Guys, help me.

From some obscure reasons I can't ask questions to the piclist, I can
only answer. Even I change an existing subject topic does not work.

I need to found urgent an european producer of NTSC tuners. Funny
isn't it ? Any help?

thx,
Vasile

--- In jallist@yahoogroups.com, "Wouter van Ooijen" <wouter@v...>
wrote:
>
> >   The wievable effect is the heating of the suppressor diodes. As
an
> > engineering rule, never choose a diode with reverse voltage
smaller
> > than 4 x supply, just to avoid breackdown.
>
> Juck. What diodes would you suggest in Eur's case (40V/1A motor)? I
can
> get SB160, but that's rated only for 60V.

   I have used some BA157 or BA159 which are not schottky but are very
good and huge reverse voltage up to 1000V.

   If the stepper does not have a heavy load even an 1N4148 my work
(200V), but often will be burned because of it's small direct current
(about 100mA, maxim 200 mA)

Vasile



>
> Wouter van Ooijen
>
> -- -------------------------------------------
> Van Ooijen Technische Informatica: www.voti.nl
> consultancy, development, PICmicro products
> docent Hogeschool van Utrecht: www.voti.nl/hvu

Hi

If your using an optically coupled triac you will need to use phase
angle control to set the lamp brightness. This means that you monitor
the mains AC (either using a transformer or capacitor for isolation*)
and detect the zero point (crossover) of the waveform. The lamp
brightness will then depend on how soon you trigger the triac after
the crossover. You should ensure that the pulse is removed before the
next zero crossing.

This is how conventional wall dimmer circuits work, and at 100-120Hz
you dont see the lamp flicker due to the thermal inertia of the
filament.

Ensure that the triacs have a good enough rating to cope with the
cold filament resistance of the bulbs.

Best Regards

Martin R Dare

* I remember Microchip having an application note for an alarm clock
which used the mains crossover for timing.



--- In jallist@yahoogroups.com, Eur van Andel <eur@f...> wrote:
>
> On 29 May, 2005, at 18:02, diederickhuijbers wrote:
>
> > I'm trying to find some information about how to connect a normal
> > lightbulb between 20 and 60 watt to a circuit with a PIC16f628, so
> > I can programmably switch the lamp on and off.
> >
> >
> > If someone has some ideas how I can create this or any
suggestions,
> > please reply.
>
> http://home.clear.net.nz/pages/joecolquitt/txless.html
>
> bottom of the page
>
> > In the future I want to attach as many as possible lightbulbs to
the
> > circuit. I think its possible to use shift registers (one shift
> > register can control 8 lightbulbs if i'm correct.)
> Yes, this can be done. A latched octal buffer can work too.
>
> A triac can't be switched off during 10ms and you might see a 10ms
on
> period. IMHO, a latched buffer would be better.
>
> ir EE van Andel eur@f... www.fiwihex.nl
> Fiwihex B.V. Wierdensestraat 74, NL7604BK Almelo, Netherlands
> tel+31-546-491106 fax+31-546-491107

> > If my description isn't clear, and you think it is worth further
> > discussion, I will attempt an ascii schematic.

For higher voltage use ordinary (not Schottky) fast recovery diodes, like
BY199 and similar.

Josef

On 02 Jun, 2005, at 02:03, bvwelch wrote:

> If my description isn't clear, and you think it is worth further
> discussion, I will attempt an ascii schematic.
This is very much worth further discussion. For an ASCII schematic, I
would recommend AAcircuit:

http://www.tech-chat.de/download.html
site is in german

that is, if you have a windoze PC. I havn't found anythong for the
Mac yet.



ir EE van Andel eur@... www.fiwihex.nl
Fiwihex B.V. Wierdensestraat 74, NL7604BK Almelo, Netherlands
tel+31-546-491106 fax+31-546-491107

--- In jallist@yahoogroups.com, "Wouter van Ooijen" <wouter@v...>
wrote:
>
> Juck. What diodes would you suggest in Eur's case (40V/1A motor)? I
can
> get SB160, but that's rated only for 60V.
>
> Wouter van Ooijen
>

I don't know if this is a stupid idea or not--  for some high-voltage
power supplies for amateur radio, we used several diodes in series. We
also had a high-valued resistor and a bypass cap paralleled across
each individual diode in the "string".

Perhaps something like that would work for your application also.

If my description isn't clear, and you think it is worth further
discussion, I will attempt an ascii schematic.

William

BYV28 or BYV27
   ----- Original Message -----
   From: Wouter van Ooijen
   To: jallist@yahoogroups.com
   Sent: Wednesday, June 01, 2005 3:36 PM
   Subject: RE: [jallist] Re: DB021 stepper driver



   >   The wievable effect is the heating of the suppressor diodes. As an
   > engineering rule, never choose a diode with reverse voltage smaller
   > than 4 x supply, just to avoid breackdown.

   Juck. What diodes would you suggest in Eur's case (40V/1A motor)? I can
   get SB160, but that's rated only for 60V.

   Wouter van Ooijen

   -- -------------------------------------------
   Van Ooijen Technische Informatica: www.voti.nl
   consultancy, development, PICmicro products
   docent Hogeschool van Utrecht: www.voti.nl/hvu




------------------------------------------------------------------------------
   Yahoo! Groups Links

     a.. To visit your group on the web, go to:
     http://groups.yahoo.com/group/jallist/

     b.. To unsubscribe from this group, send an email to:
     jallist-unsubscribe@yahoogroups.com

     c.. Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.



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

>   The wievable effect is the heating of the suppressor diodes. As an
> engineering rule, never choose a diode with reverse voltage smaller
> than 4 x supply, just to avoid breackdown.

Juck. What diodes would you suggest in Eur's case (40V/1A motor)? I can
get SB160, but that's rated only for 60V.

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: www.voti.nl/hvu

--- In jallist@yahoogroups.com, "Wouter van Ooijen" <wouter@v...>
wrote:
> >   Dave, 1N5819 is a schottky diode 1A and only 40V. Not very
> > indicated for 12V/24V steppers with heavy load where the spikes
> > could be more than 40V at power up/first step (without power
> > control).
>
> I don't see how. For a unipolar stepper the power is applied to the
> coil, with the diode blocking (non-conducting). The maximum
voltage is
> the power suplly, I see no other voltage sources. When the driver
> switches off the coil will sustain the current, producing a reverse
> voltage. But now the diode is conducting,

   An ideal diode, of course. A real diode will need some time till
switch. Time in which the voltage on the coil could increase higher
than diode reverse breakdown voltage. That's why we choose a
schottky and not a lazy 1N4007. The supposition is valid only for
serious steppers, bigger than 10W, more than 12V on coils and true
mechanical load (which means the stepper will run from inertial
movement not only from driving). And as you say, the problem is much
more real on the bipolar stepers with four suppresor diodes
connected to ground.

   Any switching coil could create a bigger voltage than the supply
itself. This is the principle for step-up generation (wanted) and
unfortunately appears at any coil switching (unwanted). That's we
need a diode supressor scheme. Fast diodes will run into the
avalanche breakdown if the inverse voltage across is bigger than the
maximum limit. The avalanche is usualy reversible but only if there
is a current limitation.

   The wievable effect is the heating of the suppressor diodes. As an
engineering rule, never choose a diode with reverse voltage smaller
than 4 x supply, just to avoid breackdown.

   This does not mean that a small 5V floppy stepper can't be
suppresed with a 30V diode. But if you'll try to run the stepper at
12KHz you will need to change the supressor and the supply voltage
too.

huge email, sorry

Vasile

  so its reverse voltage rating
> is not applicable.
>
> For a bipolar stepper the reasoning is a bit more complex, but I
still
> don't see how a reverse (for the diode) voltage can be created
that is
> higher than the power?
>
> But I am basically a software guy, so I might be missing something.
>
> Wouter van Ooijen
>
> -- -------------------------------------------
> Van Ooijen Technische Informatica: www.voti.nl
> consultancy, development, PICmicro products
> docent Hogeschool van Utrecht: www.voti.nl/hvu

On 01 Jun, 2005, at 14:39, Wouter van Ooijen wrote:

>>   Dave, 1N5819 is a schottky diode 1A and only 40V. Not very
>> indicated for 12V/24V steppers with heavy load where the spikes
>> could be more than 40V at power up/first step (without power
>> control).
Yikes, 40V max reverse. My power supply goes to 40V. There's your 40V
already.

> I don't see how. For a unipolar stepper the power is applied to the
> coil, with the diode blocking (non-conducting). The maximum voltage is
> the power suplly, I see no other voltage sources. When the driver
> switches off the coil will sustain the current, producing a reverse
> voltage. But now the diode is conducting, so its reverse voltage
> rating
> is not applicable.
>
> For a bipolar stepper the reasoning is a bit more complex, but I still
> don't see how a reverse (for the diode) voltage can be created that is
> higher than the power?
>
> But I am basically a software guy, so I might be missing something.
>
> Wouter van Ooijen
>
> -- -------------------------------------------
> Van Ooijen Technische Informatica: www.voti.nl
> consultancy, development, PICmicro products
> docent Hogeschool van Utrecht: www.voti.nl/hvu
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
>

ir EE van Andel eur@... www.fiwihex.nl
Fiwihex B.V. Wierdensestraat 74, NL7604BK Almelo, Netherlands
tel+31-546-491106 fax+31-546-491107

>   Dave, 1N5819 is a schottky diode 1A and only 40V. Not very
> indicated for 12V/24V steppers with heavy load where the spikes
> could be more than 40V at power up/first step (without power
> control).

I don't see how. For a unipolar stepper the power is applied to the
coil, with the diode blocking (non-conducting). The maximum voltage is
the power suplly, I see no other voltage sources. When the driver
switches off the coil will sustain the current, producing a reverse
voltage. But now the diode is conducting, so its reverse voltage rating
is not applicable.

For a bipolar stepper the reasoning is a bit more complex, but I still
don't see how a reverse (for the diode) voltage can be created that is
higher than the power?

But I am basically a software guy, so I might be missing something.

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: www.voti.nl/hvu

--- In jallist@yahoogroups.com, Dave Lag <daveismissing@r...> wrote:
> 1N5819 seesm to have become the universal diode for me, between
using
> them for ICSP isolation
> and switching regs /stepper stuff-  I don't seem to have any  use
for
> the good old 1N400X anymore

   Dave, 1N5819 is a schottky diode 1A and only 40V. Not very
indicated for 12V/24V steppers with heavy load where the spikes
could be more than 40V at power up/first step (without power
control).

Vasile


>
> Eur van Andel wrote:
>
> >On 28 May, 2005, at 22:53, Wouter van Ooijen wrote:
> >
> >
> >
> >>> From the documentation Wouter gave me, I used 1N4004 diodes,
which
> >>>are too slow.  Now I know why these things blow so fast, my
diodes
> >>>are too slow. I'll buy faster ones monday.
> >>>
> >>>
> >>>
> >>After that (I think yours were the first PCBs) I switched to
1N5819.
> >>Should I send you a few? PS: the PCBs are from Eurocircuits,
not
> >>Olimex.
> >>
> >>
> >
> >Thanks for the superior Sunday service from the Voti webshop!
> >
> >I assembled the kit but to amazement two output pins did not
work? I
> >don't assume you ship broken chips, so I suspect something else.
Are
> >you sure you didn't change the board design? I saw some changes
in
> >the silkscreen.
> >
> >If the board is the same, I'll test some more. I now have three
> >boards here, the two old ones work, the new one doesn't.
> >
> >
> >

> >the value including the override. So indeed shadowing makes sense.
>
> But only in the rare case when you activate peripheral, make some RMW
> operation no the tris register and then deactivate the
> peripheral. After
> this operation the tris register will contain different value
> then desired.

Indeed. Rare cases tend to take up a disproportional amount of debugging
time, so IMHO it is worth the effort to shield you from those rare
effects.

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: www.voti.nl/hvu

>the value including the override. So indeed shadowing makes sense.

But only in the rare case when you activate peripheral, make some RMW
operation no the tris register and then deactivate the peripheral. After
this operation the tris register will contain different value then desired.

Josef

> I can't make any sense of that section.

OK, I get it. When a peripheral is activated this will (in some cases)
override the TRIS setting. In that case the value read from the TRIS is
the value including the override. So indeed shadowing makes sense.

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: www.voti.nl/hvu

> Finally a good reason for shadowing the TRIS registers.
> As I read the notes on TRISB,
> it's better to use always shadow registers on the TRIS registers.
> >  http://ww1.microchip.com/downloads/en/DeviceDoc/80073G.pdf

I can't make any sense of that section. What is 'the data direction
state *on the port pins*'? There is no direction on the port pins, only
a level. And the circuit diagram shows a read of the TRIS returning the
correct info, that is: what was written to the TRIS.

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: www.voti.nl/hvu

Finally a good reason for shadowing the TRIS registers.
As I read the notes on TRISB,
it's better to use always shadow registers on the TRIS registers.
Stef

Stef Mientki wrote:

>see:
>  http://ww1.microchip.com/downloads/en/DeviceDoc/80073G.pdf
>
>Stef
>
>
>
>Yahoo! Groups Links
>
>
>
>
>
>
>
>
>
>

On 31 May, 2005, at 22:27, Stef Mientki wrote:

> see:
>   http://ww1.microchip.com/downloads/en/DeviceDoc/80073G.pdf
>
> Stef

> If RB4 goes high for any reason during high volt-
> age programming with LVP enabled, the program-
> ming will be interrupted.

Better disable LVP altogether:

> Work around
> Pull RB4 (pin 10) to ground during the initial pro-
> gramming to prevent programming interruptions.
> Once LVP has been disabled, it remedies this

[..]

> Module: MCLR/RA5 in LVP Mode
> When the PIC16F62X device has LVP enabled,
> MCLR is always enabled, regardless of the
> CONFIG register settings.
One more reason to ditch LVP.


ir EE van Andel eur@... www.fiwihex.nl
Fiwihex B.V. Wierdensestraat 74, NL7604BK Almelo, Netherlands
tel+31-546-491106 fax+31-546-491107