P&E's USB BDM Multilink won't program a QD4 - USBSPYDER08 always did - what am I doing wrong ???

[fat_wombat]

Hello again!

I've bought a fresh P&E BDM USB Multilink, rev.C.

I use it together with CW 6.2. SE and try to program an QD4 in the application.

For some reason, the USBBDM ML keeps telling me that I should recycle power and even if I do it won't program the µC - it always shows "MCU reset line Low" and launches the power recycle dialog again driving me crazy ...

For 1 1/2 years now, I've been using the tiny USBSPYDER08 stick for the same purpose, exact same electronic device, exact same cables, same IDE etc and it has NEVER had a problem with programming the µC, with more than 600 QD4 devices so far ...

Does anybody have a hint what's going wrong here?

Regards,

Emil

[kef]

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 it always shows "MCU reset line Low" and launches the power recycle dialog again driving me crazy ...

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So did you check what is voltage level on BDM connector resel line (pin4)? Is it low as stated?

[fat_wombat]

Hi kef!

Yes, the voltage on RESET is low as stated. But what does this mean? It is a tiny µC with 8 pins, I use the RESET pin #1 as timer output and have no pull-up resistor there at all, so the low level at this pin during programming should be pretty normal ccondition then? Where is the missing link?

[kef]

I would try talk with P&E about missing link.

Could you try pulling RESET high with few kOhm resistor? Any difference?

Single pin BDM first appeared on HC12 family, I think. The tiniest S12 micro has over 40 pins and RESET pin never is shared with other pin functions. To enter BDM mode, BDM pod has to set BKGD pin low and pulse RESET pin. I don't know, maybe P&E firmware for diagnostic purposes checks the state of RESET pin for all micros, not taking into account that  tiny S08 have shared or no dedicated RESET pin? But I would expect RESET pullup in multilink box. If this is the case, then  BDM RESET pin should be unused and N.C. on your QD board, is it?

[peg]

Hello,

Here is my best guess.

The USBSpyder 08 was made with these tiny S08's in mind and probably has no connection to the reset pin as there is not one there at power up.

The P&E stuff assumes the reset is there and gets around it by having you power up the board with the adapter connected.

This assumes that the circuitry connected to this pin will tend to go high when the micro is not controlling it.

To make it foolproof you could make an intervening cable adapter that does not pass RESET to your board but pulls it up.

[fat_wombat]

Hello kef & Peg,

your both gave me very good hint with the reset pin, thank you.

The reset signal/pin is obvioisly not needed indeed, never tought about this so far, but now I've cut the wire between programmer and  reset  pin of the µC and 

- USBSPYDER08 is working great without the reset signal;

- MULTILINK still tells me that the reset pin is low and doesn't want to program the µC;

I've soldered a pull-up resistor 3.3k directly on the P&Es Mltilink, between VCC and RES. Now it tells me that the reset pin is high (finally, everything in blue instead of red warnings :-)) BUT it still won't program the µC, it just keep showing the power recycle dialog over and over again ...

[fat_wombat · Accepted solution]

Hello guys!

SOLVED!

Thank you again for the fast support !!!!

Problem SOLVED due to the hints of KEF and PEG -

the MULTILINK needs badly two 3.3k (or anything less than 10k) pullup resistors

- one on RESET pin

- one on BKGD pin

of its BDM connector !!!!

It is a huge mystery for me why they are not included on the MULTILINK PCB ???

To me, I've had good reasons to not have them on my own board, since I am using the reset and BDM pin of the tiny QD4 µC for other purposes, where the pullups would have caused problems - but I really can't understand why P&E delivers a programmer without pullups, which is even not docmented at all and forces the MULTILINK to look for high levels on those pins without ever letting us know what happens??

Really poor work, P&E, had to spend the last couple of days on such a stupid issue :smileysad:

Thank you once again, kef anf peg, very good job !

[Lundin]

Most (all?) S08 have this pull-up internally.The QD4 cetainly has it. Same for the BKGD pin, there is an internal pull-up. In any manual for S08 there is a page called "recommended system connections", which hands you all pull-ups and caps on a silver plate. Just copy/paste into your PCB cad.

It seems strange that 10k (or the internal pull-ups) wouldn't work. What else have you connected to those pins? Large decoupling caps?

Also, have you connected your 3,3V supply to pin 6 of the 2x3 strip? The BDM pod will need that supply as reference to its digital voltage levels, as some S08 work with both 3V and 5V.

[peg]

Hello,

Most (all?) of these devices with re-configurable RESET pins power up as GPIO no pullup. Only when you configure it as reset or enable the pullup (if you can) does the pullup function. So it won't be there when needed. The pin generally acts as Reset when in BKGD mode. If you want to put circuitry on this pin it must be allowed to go high when you programme it.

[Lundin]

Eh? I've never heard of a S08 with GPIO on the reset pin at startup... is there even such a derivate for any Freescale MCU? I know there are a few tiny ones without a reset pin at all, but as soon as they put on a reset pin, it is a dedicated pin. QD4 is one such example.

Generally, it sounds quite stupid to have GPIO on the reset pin out of reset. That sort of defeats the purpose of having a reset pin in the first place.

No matter, it would seem that the OP had a 10k external pull-up, so the possible lack of internal pull-up doesn't explain the problem.

[peg]

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Lundin wrote:

Eh? I've never heard of a S08 with GPIO on the reset pin at startup... is there even such a derivate for any Freescale MCU? I know there are a few tiny ones without a reset pin at all, but as soon as they put on a reset pin, it is a dedicated pin. QD4 is one such example.

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Hi Lundin,

Seems you have not read too many datasheets for the last 6 or 7 years then.

My previous post was referring to the QD4 specifically and to several others in general.

QG8 is another very popular example

The QD's RESET pin actually has 4 selectable functions

It also is an input only RESET.

[Lundin]

I did check the manual before posting, as I don't know this specific derivate. Apparently, I didn't check close enough. It honestly sounded too dumb to be true... I'm normally using DZ which is an automotive-flavoured derivate using the reset pin for reset only.