View previous topic :: View next topic |
Author |
Message |
Frederik
Joined: 02 Mar 2005 Posts: 5
|
Posted: Wed Mar 02, 2005 6:08 pm Post subject: READLB entry not found! |
|
|
I have problems with my ATmega8535. I always could program my µC, but the crystal-oscillator-time did not mach! As I programmed "wait 1", he shoud wait 1 second. But hé was waiting longer. Now I understood that the ATmega's have an internal oscillator of 1MHz, and in the fuses it's selected by default. So I reprogrammed the fuses in the lock and fuse bits of bascom so I can use my external oscillator of 8 MHz, but now the µC doesn't respond anymore. Bascom do not find my µC. When I press the button 'Run programmer' he shows the message "Could not identify chip with ID: FFFFFF". Then I select the tab "Lock and fuse bits" and then he shows the message: "READLB entry not found!"
I already try to connect a functiongenerator to the erternal clock pins instead of my crystal but it do not work.
I need my µC urgent! Please help me!
Sorry for the bad english but I live in belgium.
If you speak dutch please replay in dutch!
You can add me to you msn list if you want
gulpje1@hotmail.com
Tnx |
|
Back to top |
|
|
Frederik
Joined: 02 Mar 2005 Posts: 5
|
Posted: Thu Mar 03, 2005 10:40 am Post subject: You can also reply in english! |
|
|
You can also reply in english if you want. I need to know what's wrong whit my controller, and I need a solution urgent.
Tnx |
|
Back to top |
|
|
Werner
Joined: 27 Sep 2004 Posts: 30 Location: Germany
|
Posted: Thu Mar 03, 2005 12:26 pm Post subject: Re: You can also reply in english! |
|
|
Hallo Frank,
only a speculation...
You did change the oczillator Fuses from internal to external Oszilator and not to crystal oszilator.
The atmel has no takt in fakt of this. To change it back, you have to connect an external Clock Signal to the xtal1-Pin.
Ciao,
Werner |
|
Back to top |
|
|
Frederik
Joined: 02 Mar 2005 Posts: 5
|
Posted: Thu Mar 03, 2005 2:55 pm Post subject: |
|
|
I already try to do this, but it doesn't work. I chose the first selection in the drop down menu of bascom in thelock and fuse bits-tab. I really don't now what this selection is. I going to try to connect an external clock on the pin.
But what must I do whit the other pin (xtal2)? NC? I think I must not use condensators (22p) with an external clock.
What frequency must I use for this solution? 1MHz? please tell me
Tnx a lot already! |
|
Back to top |
|
|
Werner
Joined: 27 Sep 2004 Posts: 30 Location: Germany
|
Posted: Thu Mar 03, 2005 4:11 pm Post subject: |
|
|
Hallo Frederik,
Quote: | But what must I do whit the other pin (xtal2)? NC? I think I must not use condensators (22p) with an external clock. |
xtal2 is only be used when the clock is generated by a resonator ,like a crystal resonator (aka Quarz) for example.
With internal RC-Clock xtal1 and xtal2 are NC
With external Clock-Signal xtal2 is NC
With Quarz or Ceramic Resonator xtal1 and xtal2 are connected.
Quote: | What frequency must I use for this solution? 1MHz? please tell me |
1MHz is imo good. The frequency is not so importend by using an external clock source.
Another possible reason could be, that your Clock settings are correct, but that your resonator (quarz) do not swing. To check this you need an Oszi.
Ciao,
Werner |
|
Back to top |
|
|
Frederik
Joined: 02 Mar 2005 Posts: 5
|
Posted: Thu Mar 03, 2005 5:01 pm Post subject: |
|
|
I already checked my oscillator. He gave a signal on the oscilloscoop.
Is it important that is't a perfect blok? because it's more is sinus than a blok signal! (the output of my functiongenerator) I replaced the crystal of 8MHz to a crystal of 16MHz and 32KHz, but is still doen't work.
How big must the amplitude be of my external clocksignal?
tnx a lot |
|
Back to top |
|
|
Frankeman
Joined: 11 Aug 2004 Posts: 948 Location: the Netherlands
|
Posted: Thu Mar 03, 2005 7:55 pm Post subject: |
|
|
Hi,
If you (accidentely) set the fusebit Enable serial downloading"" to 1 the ISP is not possible anymore.
In that case the chip must be erased by the parallel type of programming.
Frank. |
|
Back to top |
|
|
Frederik
Joined: 02 Mar 2005 Posts: 5
|
Posted: Thu Mar 03, 2005 7:58 pm Post subject: |
|
|
I already use a serial cable to program my microcontroller. (simple programmer)
Maybe I must use a serial programmer now. I don't know.
tnx |
|
Back to top |
|
|
Frankeman
Joined: 11 Aug 2004 Posts: 948 Location: the Netherlands
|
Posted: Thu Mar 03, 2005 8:02 pm Post subject: |
|
|
I had the same problem you have now.
Resetting the AVR in an external programmer in parallel mode (thus with the A0-A15 and D0-D7 pins) i was able to program the AVR again in ISP mode.
Frank |
|
Back to top |
|
|
|