programming P89LPC935

[sirivlis]

Hi

I use lpc935fa in my project.
To program it via isp (Flash-magic)i use max232
and 2 npn transistors to go from 3.3 to 5 volts for txd and  2 npn transistors to go from 5 to 3.3 volts for rxd.
(i will use max3232 but it will take 15-20 days to get it)
Everything works fine with:
-------
P89LPC935FA
CD3829
TtG0439   A
-------
Yesterday i receive
-------
P89LPC935FA
Pb-Free Package
452004
-------
Flash magic can't communicate with these new chips.
After reset, i measure 0 volts on pins rxd and txd.
Seems like they are in input or open drain mode.

Excuse my bad english.
thanks for any help.

[erikm]

as answered in cross posting at 8052,com


To program it via isp (Flash-magic)i use max232
and 2 npn transistors to go from 3.3 to 5 volts for txd and 2 npn transistors to go from 5 to 3.3 volts for rxd.

As long as the MAX232 is powered by 5V there is no need for the 2 NPN transistors. Using a 3V3 powered MAX3232 is far better, but a MAX232 with Vcc 5V will work, just not quite as noise resistant. Do you have the right capoacitors on the MAX232 (there are so many variants with different capacitor values - doub naah triple check).

There is no reason whatsoever that the other LPC935 should not work, check your connections.

Erik

[sirivlis]

thank you Eric for answer.

I tried max232 without transistors.
Everything works fine with old chips.
I measure the supply current(max232 not connected).

8 ma for old chips after "touchless" and restart(when they are ready for ISP).
And
0.2 ma for the new ones.
It looks like they are near power-down mode.
(i test 5 old chips in 5 boards and 15 new chips on the same boards).

lambros

[sirivlis]

cross posting at 8052,com

Roberto munoz wrote:

You can program one of yours good 935 as ISP to ICP bridge via ISP and then you can test the new 935 in ICP mode. Please check the Joe´s ICP improvements docs at flashmagic forum http://www.flashmagictool.com/assets/resources/ICPBridgeVddSwitch.pdf

Regards,
Roberto
----------------------------------------------------
Thank you Roberto for answer.

I show that ICP programming requires MCB900 board
which i don't have (AN10258).
With 3 reset pulses P89LPC935 goes into ISP mode only
or it can then programmed with ICP?
If the answer is yes,
then i can upload prog9x.hex to a good chip
to make the bridge and try to program the new chips
with flash magic.
(If flash magic can program ICP with option
DON'T use RTS - DTR)
I'll ask and in Flash Magic forum.

Lambros

[Je Gold]

It might be better for you to purchase a professional  ICP tool.

Here's one
For 1st time users of the LPC900 series .... a profesional ICP tool and a Keil MCB900 is a good start.
http://www.teamfdi.com/products/usb-icp/usb-icp.shtml

OR

http://www.lpctools.com/index.asp?PageAction=VIEWPROD&ProdID=83

Or others...

In relative terms these tools are not expensive  <$100 USD  + Freight.


You could build your own ICP Bridge as I have done and detailed on the flash magic web site.. but but it does require intermediate to high level experience on micro controllers, as a general rule.

Program on of you good LPC935's with the ICP Bridge code (prog90xx.hex) and use the additional bridge hardware to do the 7 pulses on RESET after POR.

Joe

[sirivlis]

 cross posting at 8052,com

I got 37 new chips today
P89LPC935FA
A1039300--
YtG0704B
I already program 5 of them and everything is ok.
I'll follow Joe's advice and try FDI Programmer for ICP.
I'll keep the bad chips to "play" with them later on this summer
when i'll have time.
Maybe Eric is right about ESD.
Eric,Roberto, and Joe thanks again for your answers.