yet another DS89c420 post

[nshemon]

device security is low ds89c450

I'm sorry to be posting yet another question about how to get the boot loader to connect to my computer...but here it goes.

I'm using the MTK program, and have tried all different Baud rates. Somewhere on this forum I read about using 115200 and 57600 baud rates(I have using a 11.0592MHz crystal). These have resulted in the "best" outcome.

After some google searches, I found the following schematic: **broken link removed** (the picture is on page two). I've made sure that the RST pin is on high, and the EA pin is low. My original setup was from the pdf on MAXIM's website (In system programming with 8051-Based Microcontrollers), but they don't show every connection...just the basic ones.

When I try to connect using MTK i get two random characters in green (like Ca or Tu) then it says "Unable to establish communication with target". I'm not sure if any of you have see this before, but if anybody could help out I would appreciate it very much.

Added after 1 hours 16 minutes:

I also just tried out the setup that I found on this post: . But I got the same results.

Could it be my computer? It's an old Gateway 2000...maybe i'll try to find another computer.

 

[IanP]

lb bits are already set ds89c450

25 Apr 2005 3:30 Re: DS89C450 programming (again ? )

--------------------------------------------------------------------------------

If you use MTK and 11,0952MHz quarz the proper communication between PC and DS89C450/4.. can be established at 14,400bps.. so configure your serial port for that speed.

Before you try to establish communication DO NOT FORGET aboyt setting TARGET CONFIGURATION Flesh Security to Level 4 (if you leave Level1 you will lock the security bits).
With all this done you can press CTR+L = connect to loader (or TARGET ...) and you will see the following:
Quote:
DS89C450 LOADER VERSION 2.1 COPYRIGHT (C) 2002 DALLAS SEMICONDUCTOR<0D><0A>
> 89C450 LOADER VERSION 2.1 COPYRIGHT (C) 2002 DALLAS SEMICONDUCTOR
> R<0D><0A>
R<0D><0A>
LB:00 OCR:FF ACON:1F CKCON:01 P0:FF P1:FF P2:FF P3:FF FCNTL:B1<0D><0A>
>W CKCON 0<0D><0A>
W CKCON 0<0D><0A>
<0D><0A>
> W ACON E0<0D><0A>
W ACON E0<0D><0A>
<0D><0A>
> W OCR 0<0D><0A>
W OCR 0<0D><0A>
<0D><0A>
> W LB 7<0D><0A>
W LB 7<0D><0A>
<0D><0A>
>

Now you will be conected ...

As far as hardware is concerned, if you have the DS89C420 in a prototype board, forget about 74125 and DTR signal to control it, just connect EA-->0V, PSEN-->0V and RST-->+5V. I hope you have the "level conversion" between COM(X) and Rx/Tx of MCU sorted out (by connecting MAX232 or similar) ..
Now, try to follow advices from the above quotation, and for more use SEARCH and keyword: DS89C450 ..
If you still have problems in establishing communication between PC and DS ..come back ..

Regards,
IanP

 

[nshemon]

89c450 voltmeter

yeah, I found that post you quoted earlier today and tried the things it said (namely got rid of the 74125 and DTR signal). I am using the DS232A for a conversion between the cable and the microcontroller. Same results though. I did realize, though, that i am using Ceramic Disc Capacitors, could this be my problem? Should I get electrolytic ones? Why would there be a difference?

Thanks.

 

[IanP]

Ceramic caps do not matter much, as the DS232 needs any 100nF (0.1µF) ..
Double check if you have Rx of micro nonnected (through DS232) to Tx of PC and Tx of micro to RX of PC ..
Try 19,200kbps ..

<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.

þ<0D><0A>
<0D><0A>
DS


DS89C450 LOADER VERSION 2.1 COPYRIGHT (C) 2002 DALLAS SEMICONDUCTOR<0D><0A>
> 89C450 LOADER VERSION 2.1 COPYRIGHT (C) 2002 DALLAS SEMICONDUCTOR
> R<0D><0A>
R<0D><0A>
LB:01 OCR:00 ACON:1F CKCON:01 P0:FF P1:FF P2:FF P3:FF FCNTL:B1<0D><0A>
>device security is Low,Cannot set to None
Unable to establish communication with target.
Check connection to target system or consult help files.
L
<0D><0A>
E:LOCK
E:LOCK BITS ENABLED<0D><0A>
> BITS ENABLED
>

As you can see initially I coudn't establish communication with the micro, so I reset the micro (power OFF and ON) and I re-issued the CTR+L (connect to Loader) command from TARGET menu ..
Then I issued the "L" command from keyboard (L+ENTER) and the micro is ready ..

Regards,
IanP

 

[nshemon]

Wow, i think i found my problem...my power source seems to flicker on and off. I suppose i didn't notice it before because my LED was behind a large enough resister to delay the flicker? Anyway, it's time to search the house for some sort of 5V power source.

 

[nshemon]

ok, I have a very noobish question....is it convention for the pin with the dot next to it be number 1? or does it change from chip to chip? Becuause i think I may have my DS323A hooked up backwards. I don't think it is though, because I don't get the error "didn't receive R prompt" anylonger, and the debug shows a green R (which I assume is the R prompt). So there has to be some sort of communication going on there...right (it's still unable to connect)?

 

[IanP]

Most (if not all) ICs have pin 1 marked somehow (dot,..) ..
If I were you I would first check the DS232 using a voltmeter and a power supply (without MCU connected) ..
Connect pin 14 with 13 and 7 with 8 (see picture below) .. You should read on both TX pins (14 and 7) negative voltage between -5V and -9V, and on both RXTTL pins (12 and 9) level H TTL - voltage between +4 to +5V ..
Now shorten pins 10 and 11 to 0V --> you should reed +5 to +9 (7 and 14) and TTL low (9 and 12) ..
This test will ensure that your DS232 is OK ..

Single green "R" is not enough, as far as the communication between DS89C420 and PC is concerned .. If communication is established you should have .. well, see my previous post for what you should have ..

Anyhow, first check the RS232 drivers and receivers ..

Regards,
IanP

 

[nshemon]

So yes, my RS232 chip was upside down....But I also ordered some samples of the DS89c450 instead of the 420. I successfully connected!! Thank you for everything!

Nathan