LPC922 ISP flashing problem

[Janez]

Up to now I used WINISP application to flash P89c51Rx2 microcontrollers without any problem and without special HW except MAX232 as voltage level interface between PC and microcontroller.
Recently I received some LPC922 test samples. According to documentation I read it should be no problem to flash them similarly as P89c51Rx2 except there is a different HW procedure to force them into ISP mode. I build a special microcontroller circuit to form three 10us pulse/pauses and use Flash magic as PC application. The LPC922 respond on "U" but always wrong (usually with 00h). I tried to wake up it with all most Baud rates but without success. I also changed the PC but it was the same result.
When I changed Flash magic with WINISP application just to see what will happen, the LPC922 always respond on "U" correctly, but of course I can not use it for flashing. When I tried to Blank check I also see correct echo response on "U" and even for first block.
Has anybody an idea what could be wrong?
Is it possible to flash LPC9xx with Flash magic and COM port HW interface used only MAX232 and special 3pulse circuit?

thank you very much for help in advance

[Andy Ayre]

Without knowing how your circuit works I cannot tell what the problem could be. There is a circuit designed by Keil Software that allows Flash Magic to generate the pulses and all I can tell you is that lots of people are using this without a problem. You might want to study the Keil circuit diagram to see if there are any flaws in your circuit and the assumptions you might have made when designing it.

I would also double-check the timing of your pulses, including tVR and tRL.

The Keil circuit diagram is described in the Flash Magic application note on how to enter ISP mode using handshaking signals.

[erikm]

I do not know if this works for the 922 (its for 932), but have a look

http://www.8052.com/users/erikm/NoTouch932.phtml

Erik

The basis for the NoTouch is that all chips will load once.  If at that time you get NoTouch in you will always be able to ISP (unless you have a program error before that code is reached).

Therefore I suggest that NoTouch (for the biggies the 'backdoor')  ALSO be located immediately after the jump from 0 conditioned on a pin held down.  That way, if a program error occur NoTouch works as OneTouch.  The 'standard' activation of NoTouch will still be no touch.

[Huynh]

Any one can set the I2C bus works well?
I have trouble about this.
Anybody had made some code for this? can U give me some!
I can't even try to test does it work! Can U help me!
Thanks!
PS: I tried to send the data between two lpc922!

[erikm]

Anybody had made some code for this? can U give me some!

You are contradicting yourself you say "Anybody" and then you ask micro to give you some.

Anyhow this is a FlashMagic forum so the question is off-topic.  lose the Stupid Monkey **** and post at 8052.com

Erik

[mahler]

Actually, I have used Transistors to form a interface circuit with single +5V Power supply, which is obviously not as good as your MAX232 circuits. Moreover, the reset pulse generator is made of 6M XTAL + 74HC4060 + 74HC00*3 + button.

It works by FlashMagic on LPC922. The only problem is that with this method only 9600 BAUD RATE is accepted, in stead of the recommonded 7200 or others.

My tuning steps:

Use COM testing software to send and recieve "U" after 3 reset pulses. If the result is as expected, the HW is at good working. Then put the FlashMagic on the table.

Wish it helps!

[erikm]

"Actually, I have used Transistors to form a interface circuit with single +5V Power supply, which is obviously not as good as your MAX232 circuits. Moreover, the reset pulse generator is made of 6M XTAL + 74HC4060 + 74HC00*3 + button."

In other words, your question is:

When I do everything wrong, how come it does not work.

Erik

[mahler]

"In other words, your question is:

When I do everything wrong, how come it does not work."

Hi, Eric.

What I want to do is to confident Janez that FlashMagic can work on LPC922 even through the simplest interfacing circuit. If this makes you feel not so good, I apologize for it.

[erikm]

FlashMagic can work on LPC922 even through the simplest interfacing circuit

BULLSHIT

that does not change the fact that it MAY with luck

erik