Cann't excute the "Erase all flash" for 89c61x

[CARPER]

hi:
    There are some questions about erase the 89C61x.
    * How to "perform the all flash erase"
    When I select the "Erase all Flash+security+clks" and click the "start",then the status show that is erasing.But It takes long long time and can't finish.
    At first I can program the device and the second  I cann't program,the message show that cann't connect the device!
     Are there any special requirements for firmware?
   
     thanks for all
                           carper
                          2004-8-9

[erikm]

>>At first I can program the device and the second I cann't program,the message show that cann't connect the device!
Are there any special requirements for firmware?<<

That show ONE thing: your "kick into ISP" circuitry is wrong.

as always: "why not use NoTouch.

Erik

[Andy Ayre]

Yes, double-check your hardware entry method and ensure it matches the requirements on the datasheet. Make sure you don't have glitches or ripple on your power supply, as that can upset the device.

Let me know if this doesn't help.

[carper]

there are two questions:
  1, I can program the device at the first time, It's show that the circuitry is correct. Do you think so?  At the second time  cann't program . The flashMagic cann't connect the MCU.I think the reason is as follows : the status vector had been changed(It does equal to zero). When the system power on,MCU would execute the program from 0000H.  So FlashMagic cann't connect the MCU.
   2,   In the flashMagic  click the menu "ISP"  and execute the "Status Byte...." ,the message will show "Also note that After performing the full flash erase  the status byte is set to 0xff" .  If I can erase the full flash,it will be sucessful.
      Now I Cann't erase the full flash ,it will be dead.
      As follows is my circuitry :
             1),PSEN to GND
             2),EA/VPP  input 10 V  >VCC  from DC power supply.
             3),Reset :use the MAX810L
             4),ALE  pin  is hanged.
      Are there any questions in these descriptions ?
   thanks!

 carper
2004-8-10

[Andy Ayre]

Right, because the status byte has now changed to execute code, when you try to enter ISP mode, that is when you are really testing the ISP entry method. Because the device came from the factory with the status byte set to FFH, you might have thought that /EA, PSEN, etc. were doing something, but really they were being ignored.

Try pulling P2.6 and P2.7 high during reset. I know it is required for the 89C51Rx2Hxx and the 89C5166x, but I don't know if it is needed for the 89C6xX2.

[carper]

1,   I have pulled the p2.6 and p2.7 to high. It is no use for  Erasing all flash. other related attentive points about the ISP needed ?

2,   About ALE , When pull the ALE to High , the power cann't provide the serial voltage, and the Max810L always reset the device periodical.
    when   I programed the 89c61x2 successfully ,the ALE pin was hanged. This time the ALE pin always produce  the pulse  frequence equal Fosc/6.
    My problem is how to process the ALE pin.


thanks
carper
04-8-11

[Andy Ayre]

ALE toggles when the device is executing code. If you read the datasheet for the ISP entry, it states that ALE needs to be high or not connected on the edge coming out of reset. At this point ALE is not toggling as the device is in reset.

Maybe your MAX810 is interferring with getting into ISP mode?