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troubleshooting 8051

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Moderators: Ajay, Junied , abbas1707, Arun Kumar V, pdi33, Shailesh NAYAK, ۞ TPS ۞, shyam, sashijoseph

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luckynumber

Sat Jul 26 2008, 12:12PM

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is there anyway to test whether my 8051 is still in good condition? and also max232?

Arun Kumar V

Sat Jul 26 2008, 06:41PM

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Hi Lucky number,

what is the problem/s you are facing with them ?

Arun

luckynumber

Sat Jul 26 2008, 07:10PM

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Hi Arun,

Thank you very much for your reply. Currently I am trying to set the AT89C51ED2 Microcontroller into Bootloader Function in order to program it. But I keep prompting with "Timeout Error" everytime I am trying to interface MAX-232 with AT89C51ED2 using ATMEL Flip Program. Can I know why I keep getting the error message? What is the possible cause of this error?

Arun Kumar V

Sat Jul 26 2008, 07:37PM

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Hi Lucky,

this problem arises when the serial Programming Software ( here it is FLIP) sends a alert command to the On chip Boot loader and expects response from the boot loader.

the serial programming makes a number of attempts to evoke response from the boot loader and finally gives up saying " timeout error".

Possible causes of error:

1) micro doesn't "see" the incoming command - incorrect wiring of Max232

2) the software Transmits command but doesn't receive response from Micro - internal RS232 chip failure on the motherboard ( it happened to me - had to change the motherboard)

3) micro serial port pins damaged (externally or internally)

4) wrong wiring of DB9 serial cable

check for the above and hopefully your problem would be resolved !

Arun

sashijoseph

Sat Jul 26 2008, 08:12PM

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@luckynumber
Also tell us how you've wired the EA and PSEN pins.

Let there be music........

luckynumber

Sat Jul 26 2008, 08:33PM

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Dear Arun,

Thank you for your helpful info.

This is my Schematic layout for the MAX232 and AT89C51ED2. Another one is the schematic for MAX232 with diode. Can I know the difference between these two configuration? Which is better?

Basically these are the steps taken to set into Bootloader Function:

i. Set the PSEN to ground.
ii. Press the RESET button which will supply 5V to AT89C51ED2 RESET Pin.
iii. Set the PSEN to 5V.

Are these steps correct in order to triggered the chip into Bootloader Function?

duncan

Sun Jul 27 2008, 07:30AM

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Dear Arun,

I set the EA pin to 5V as well.

Arun Kumar V

Sun Jul 27 2008, 10:40AM

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Hi Lucky & Duncan,

i feel the micro has not entered the ISP mode, that may the reason for error.

follow these steps:

1) switch off the supply to the board

2) wire the EA 31 pin to +5V

3) wire a push button switch between PSEN and GND also use a 1.5K resistor (pull down resistor) like this : PSEN-------Switch leg 1-------switch leg2----1.5k-----GND

4) Switch ON the supply

5) Press and hold down Reset button

6) Press and hold push button which connects PSEN to GND thru 1.5K resistor

7) release the Reset button ( while still holding down the PSEN Button)

8) release the PSEN button

9) the Chip will be in boot loader mode and then use Flip to communicate with the chip, also remember to use 11.0592 Mhz Xtal (this value works for all baudrates)

All the Best !

Arun

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nischay kumar

duncan

Sun Jul 27 2008, 07:13PM

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Dear Arun,

Thank for your help. l'll try the step.

sashijoseph

Sun Jul 27 2008, 08:13PM

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@Lucky
The 1st schematic you posted is horribly incorrect.Hope you haven't used that.
Make corrections according to this schematic which is taken from the serial tutorial at this very site...