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HC908 problem with mon08

Hi,

I have some trouble with connecting my USB-Pemicro pod to a MC68HC908QY4.

The first design I built had a socketed DIP chip onboard and worked as expected. Then I switched to an SMD and now I can not connect anymore. Now it tells me:

Postload command file correctly executed. Opening USB Port 1 ...MON08 MULTILINK Interface cable detected - Flash Version 2.11 Could not measure target baudrate. Opened. Starting powerdown reset sequence ...

Trying Security $FFFFFFFFFFFFFFFF Invalid/No Response. (Failure of 68HC08 to respond properly. Check connections.)

Which I think is a good Idea - if I hadn't already done it often enough :-) (yes - for the different SMD pinout) and I also can not find any shorts or broken lines.

When I watch the connection process with a mixed signal scope I can see all MON08 signals do what they are in my eyes supposed to do, just PTA1 (directly connected to pod) will not go up far enough (goes from low to some

800mV while trying to connect). Also the signals look qite lousy (a lot of 10MHz noise from the pod) which they do on the DIP-Board, too.

Also if i am simply wire-wrapping a QY4 SMD type to my pod and pull up the reset pin I have the same behaviour while a wire-wrapped DIP board with the same connections works perfectly.

Could it be that I have missed some Information about the SMDs or is it the same die?

Do DIPs have any additional Cs or protection inside?

Any Idea?

Thanks, Henrik

Reply to
Henrik
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Have you checked the levels of all pins against the table in the manual listing the requirements for entering monitor modes? You have to supply proper logic levels to some of them.

Do you have 9.83something MHz clock source? If you rely on internal osc - the OSCTRIM value may or may not be factory programmed. If it's not programmed the communication won't work. And contrary to what the manual says it was't programmed in any of the chips I had.

Reply to
Grzegorz Mazur

Yes, I have. I have a very nice mixed mode Scope on my Desk where i can see exactly what happens on VDD, VSS, PTA0, PTA1, PTA4, OSC1, RST and IRQ. Everything looks fine, just the stupid PTA1 won't go high because obviously the smd is driving it low (Pod drives high when contact is open).

... anyway it still should work when the chip is empty which it does not, right?

Yes, it is in the USB adaptor.

Ah!

I already wondered about that. I can't monitor my other toys without clk. The Pemicro manual is not too clear about that either. It just says "Pin x is CLK", which I interpret as "connect directly to OSC1 as with the clocked MAX232 circuit". I hope that is right.

Thanks for the help, Henrik

Reply to
Henrik

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