Searching \ for '16f877 parallel programer problem' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/microchip/devices.htm?key=16F
Search entire site for: '16f877 parallel programer problem'.

Truncated match.
PICList Thread
'16f877 parallel programer problem'
1999\11\28@162240 by Jake Szot

picon face
Help!

A classmate and I are making a PIC16f877 programmer as a project in one
of our courses and we've run into a problem. The PIC will not let us
read data (properly) or advance the program counter while in program
mode. Here are the steps we go through to program a location:

0. Issue a Bulk Erase Programing Memory
1. Reset the PIC by keeping RB6 and RB7 low and then bringing MCLR from
0v to 12.5v
2. Issue a Load Data for Program Memory command (6 clks) followed by
clocking in the data (16 clks)
3. Issue a Begin Erase Programming Cycle command (6 clks)
4. Issue a Read Data From Program Memory (6 clks) to see if the data
went in properly
5. Change our Data Out to High Impedance
6. Issue 16 clks to read the data from the PIC

What comes out from the PIC (during these 16 clocks) is not what we
programmed. It is all 1's.

Now, if we perform a reset (ie step 1) and issue another Read Data From
Program Memory (ie steps 4 through 6) we receive the correct data that
we entered in!

Further more, if we try to program the first two memory locations ie:

1. Reset the chip
2. Issue a Load Data For Program Memory
3. Issue a Begin Erase Programing Cycle
3. Clock in some data
4. Issue an Increment Address
5. Issue a Load Data For Program Memory
6. Issue a Begin Erase Programing Cycle

Then reset the chip. We can read back the first location ok however the
second location does not give us our data. Again it is all 1's.

Any help would be greatly appreciated. Please try to respond to
spam_OUTjakeszotTakeThisOuTspamhome.com as I don't know if I will be able to monitor this
list for responses.

Thanks!

-Jake

1999\11\28@171726 by Robin Abbott

flavicon
face
Jake

This may be a stupid question but are you waiting 10mS (check data sheet for
exact time) for the PIC to complete the erase-program cycle before reading
back ? (BTW program only is faster)

Robin Abbott - .....robin.abbottKILLspamspam@spam@fored.co.uk

**************************************************************************
*
* NEW from FED - WIZPIC - visual PIC development
*     - see web site for more details !
*
* Forest Electronic Developments
* http://www.fored.co.uk
*
**************************************************************************

{Original Message removed}

1999\11\28@204002 by Tony Nixon

flavicon
picon face
Jake Szot wrote:
>
> Help!

When you apply power and VPP to the chip, are you allowing some time
between for things to stabilize before trying to program/read it.


--
Best regards

Tony

http://www.picnpoke.com
Email salesspamKILLspampicnpoke.com

1999\11\28@210532 by Jake Szot

picon face
> When you apply power and VPP to the chip, are you allowing some time
> between for things to stabilize before trying to program/read it.

We apply power to the chip (ie Vdd) constantly while it is in the
programer. Then we bring MCLR to Vpp to begin programing. Seconds if not
minutes elapse before commands are sent to the PIC.

-Jake

1999\11\29@164014 by wzab

flavicon
picon face
On Sun, Nov 28, 1999 at 03:10:07PM -0600, Jake Szot wrote:
> A classmate and I are making a PIC16f877 programmer as a project in one
> of our courses and we've run into a problem. The PIC will not let us
> read data (properly) or advance the program counter while in program
> mode. Here are the steps we go through to program a location:

[snip]

Hi,
I had a similar problem with programming of PIC16F877.
It's description may be found at:
http://www.infosite.com/~jkeyzer/piclist/1999/Aug/1898.html

However in my case the programming of code memory worked correctly, but
verification of data EEPROM failed (the PIC returned "0" values
independently on what I've programmed). Up to this time I haven't found
the solution of this problem, however with this exception the programmer
works fine...
If you get any answer to your question, which may be useful to solve mine,
please Cc it to me...
--
                       TIA
                       Wojciech Zabolotny
                       http://www.ise.pw.edu.pl/~wzab

http://www.freedos.org  Free DOS for free people!

1999\11\30@041141 by Dr. Imre Bartfai

flavicon
face
Hi,

as I mentioned, PIC16F877 wishes - in a strange way - a lower value of
pull-up resistor for his data line during programming. I succeeded with 1
kohm instead of 4.7 or 10.

I hope this experience may help you.

Regards,
Imre


On Mon, 29 Nov 1999, Wojciech Zabolotny wrote:

{Quote hidden}

More... (looser matching)
- Last day of these posts
- In 1999 , 2000 only
- Today
- New search...