Problem with AT89C51CC03

I use flip 3.3.4 upload HEX to AT89C51CC03,When Flip running ,AT89C51CC03 can run afteer reset circuit ; Close Flip,At89C51CC03 can't run.Why?

Filp software setting :
BLJB=1, others use default

Nobody can help me ?

giveyou said:

Nobody can help me ?

Click to expand...

Try posting your programming circuit, including your reset circuit.

Operating system? Serial port, USB?

Debugging:

What have you tried?
Does the chip program & verify?
Can you read the chip contents successfully?

My OS is WinXP Pro With SP2, Use Serial port upload HEX.

when I run flip ,MCU can run after circuit reset;
close flip, MCU can't run.

you did not answer the above questions:

Try posting your programming circuit, including your reset circuit.

If you don't have a diagram of the circuit, post (or describe) YOUR RESET CIRCUIT!

look at my post here:


Debugging:
Does the chip program & verify?
Can you read the chip contents successfully?

Check the PSEN pin. It must be left floating (or high) when running MCU. Some programmers hold this pin low via one of the serial port pins. This situation has caused me a great deal of grief in the past!

IF this is the case, I would connect a jumper to the PSEN pin to disable it when running your MCU.

I disconnect hardware with serial port ,and MCU can run . I want to know why?

thanks for your help and happy new year.

serial circut as below

Try isolating the problem further by removing the 10 k resistor to the base of the transistor going to the reset pin.

praveensss said:

Try isolating the problem further by removing the 10 k resistor to the base of the transistor going to the reset pin.

Click to expand...

if this works, cut the track and install a jumper (or slide switch) before the resistor.
(Or see option #2 below)
To run your board, remove the jumper or shut off the switch.

I would also test the PSEN level when the circuit is powered up and connected to the PC (after programming the MCU)

IF PSEN remains low, then you need to install a jumper on the base of that transistor (before the resisitor).

Option #2:
Don't cut any tracks on your board.

This circuit (allowing the PC to control PSEN & RST) is really unneccessary. For more reliability, I would remove both transistors. The reset circuit is there. The PC does not need to control the reset pin.

The PSEN pin must be low when programming. All you need is a switch or a jumper on the PSEN line to GND. I would replace SW6 with a slide switch or jumper.

This will eliminate all of your headaches.

Remember that PSEN must be low before circuit is powered up in order to successfully enter ISP mode.
Good Luck