8-bit Microcontrollers中的主题 9S08 with BDM

9S08 with BDM

yb — Sat, 04 Feb 2006 16:02:52 GMT

Hi,

Since I've used 9S08GB32 and the P&E BDM pod, I've seen the same big problem : in debug mode (with pod plugged and in step by step debug for example), if I light a little lamp near my system, the pod generate a RESET to the 9S08 and come back to the start of the startup.c in STOP mode.

The problem is seen with any electric consumer (PC monitor, soldering iron...).

Actually, I'm developping a product with a motor control (H bridge with MOSFET) and it's of course impossible to use the debug mode for this reason

I must remove the BDM cable to avoid these reboot.

Can I disable the RESET pin on 9S08 ? I have looking for this option, but I'd find nothing.

Any ideas ?

Regards,

Yvan

Re: 9S08 with BDM

Nabla69 — Mon, 06 Feb 2006 16:56:12 GMT

Hi Yvan,

Have you tried with a smaller Pull-up resistor on the Reset PIN like 4.7k ?
I also think about faster decoupling of the supply pins very close to the MCU to absorb noise in the tracks.

Alvin.

Re: 9S08 with BDM

yb — Mon, 06 Feb 2006 17:21:37 GMT

Alvin,

I've even tried a 680 ohm pull up...

The 3 100nF capa are soldered closest as possible (less than 2mm, below the 9S08).

Yvan

Re: 9S08 with BDM

Nabla69 — Mon, 06 Feb 2006 18:31:52 GMT

[EnglishAccent Mode]
Shocking !
[/EnglishAccent Mode]

Do you only have the reset when the BDM is on, or even when the MCU is alone in its applications.

If it's the former, the interface may generate a reset when it receives the noise. Grounded kitchen foil around the purple box ? I know it looks like cooking... but it should improve EMI immunity of the BDM interface.

If the latter, can you capture/observe spikes on any particular pin ? This would allow to isolate source and then treat it...

You probably have better experience than me on this, but a new light can always be beneficial .

Alvin.