DS89C450 programming (again ? :P)

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chupos

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ds89c450 bootloader

Hi,
I read quite a lot of threads about this, but I didn't get some things. I've mainly interfaced it using this:

But with some slight changes, that I think are just errors on that, that is, the VS+ of the DS232 tied to the ground, it should be tied to Vcc.
Well, my problem is that I get this:
"Did not receive R prompt. Unable to establish communication with target. Check...."
when trying to "Connect to Loader" from MTK.

Thanks in advance,
Alex
 

So you are stating that you cannot connect your micro to the PC?

Can you show us your schematic? Have you used the right capacitors for the RS232 level converter chip?
 

K, here we go
schematics as pdf and as Protel Schematics:
**broken link removed**
**broken link removed**
btw, I forgot the crystal in the schems, but it is also connected, an 11 MHz crystal
Thanks for your help,
Alex
 

Have you searched the Microcontrollers' Section for the DS89C420 programmer that uses MAX233? I had just posted its schematic in the board and its PCB layout is also on the board.

If my reply helped you, you can say thanks to me by pressing the HELPED ME button.
 

    C

    chupos

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Well, I know u posted some schems here of a programmer, but I'd really love to know what's the problem with mine
Ya, you are helping me actually
 

In your DS232, is it really configured like that? I have no experience using the said IC.
 

Yes, I used the example schematic from the DS232A datasheet
 

Have you used polarized 1uF capacitors or just ceramic capacitors?

C5 must as close enough to the DS232.
 

they are polarized capacitors, and C5 is very near the MCU
 

C5 not must very near at MCU they must be close enough to DS232, youc an use another decoupling for MCU.

Crystal is 11.0592 Mhz exactly? What baudrate did you used?

Have you followed the correct configuration for crystal?

Your com port settings, have you checked it also?

Have you checked it with hyperterminal if working?
 

mh, moved C5 near DS232A, still the same.
With hyperterminal it seems to establish connection on both COM ports, but there's only one COM port used.
Yes, the crystal has exactly that frequency.
I tried with all baud rates, anyways the problem doesn't seem to be with the RS-232 driver, but with the MCU somewhere, as it says that it didn't get the R.
 

Have you tried another MCU? Btw, the problem is you cannot connect right? Check also if LM7805 is enough to drive the bootloader and DS232, maybe your LM7805 is the low current version.
 

Didn't try with any other MCU, gonna do that now.
the 7805 supplies enough current, already looked at that, as that was one of my first problems I had until I substituted the MAX6250 with the 7805
And... it seems to connect, but when you use the "Connect to Loader", it doesn't connect to the loader, althou it seems to connect to the DS232
 

Try to connect with Hyperterminal and press the ENTER key, do not forget the ground of the RS232 cable also.
 

lol, is it really needed, the ground of the RS-232? cause that's something I never connected. Anyways, should I connect it just to the common ground and the minus of the power supply?
 

There must three wires connecting your programmer to the PC, they are RX, TX and GND. Just connect them to the negative of your power supply.
 

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    chupos

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gonna try it in a sec and tell you, thanks

Added after 10 minutes:

doesn't seem to work

Added after 2 minutes:

This is what I get with debug mode enabled:
<0D><0A>
<0D><0A>
<0D><0A>
<0D><0A>
<0D><0A>
Unable to establish communication with target.
Check connection to target system or consult help files.

Added after 4 hours 59 minutes:

any other ideas/suggestions/corrections ?
 

Hi Alex,

Did you try checking if the oscillator is running or not? Maybe the crystal is not working or perhaps it's caps are busted... I'm assuming you are doing this all on a breadboard. Crystals tend to hate breadboards
 

couldn't test the crystal cause I moved to a new house a few days ago... and my oscilloscope is... somewhere, hiding betweeen thousands of other things :/

Added after 56 seconds:

anyways, is there some other way to test a crystal?
 

Try to replace your crystal and run your programmer, try the 19200 or 9600 baudrates.

Check also your capacitors used with the crystals.
 

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