8-bit MicrocontrollersのトピックRe: AW32 problems in 5V

AW32 problems in 5V

JohnnyS2K — Fri, 04 Jul 2008 09:20:43 GMT

Hi to all,

I have made a little LED blink application for the AW32 MCU (MC9S08AW32 CFGE) and programmed with the DEMOQE board through the BDM connector. I have tested the application with a supply voltage of 3.3V (BDM connector) and it works fine, but, when I supply the AW32 MCU with 5V (in other board with the LM2575-5.0) the power supply enter in short circuit (protection) and after some trys the AW32 MCU is damaged entering in internal short circuit (the BDM resets itself when I connect the MCU).

My question is: the AW32 can really use 5V as supply voltage? Does someone have made some project with the same components? What can be wrong?

Thanks

Re: AW32 problems in 5V

JimDon — Fri, 04 Jul 2008 09:25:02 GMT

The AW32 is good at 5V.

Please be sure you did NOT connect VDD pin from the QE board.

Re: AW32 problems in 5V

JohnnyS2K — Fri, 04 Jul 2008 09:32:22 GMT

Hi JimDon,

I'm only connecting the VDD pin when I program the MCU, and in that way the MCU works, but when I disconnect the BDM cable and put the MCU on other board with a 5v supply then problem occurs.

Thanks

Re: AW32 problems in 5V

fabio — Fri, 04 Jul 2008 18:58:25 GMT

Hi,

Are you sure that the whole chip is being supplied with 5V (including VDDAD)?

The DS states that the maximum allowed difference between VDD and VDDAD is 100mV.

Best regards,

Message Edited by fabio on 2008-07-04 09:01 AM

Re: AW32 problems in 5V

JohnnyS2K — Fri, 04 Jul 2008 20:34:09 GMT

Hi Fábio,

The VSSAD, VDDAD, VREFL and VREFH are left unconnected in the same fashion as when I supply the MCU with the BDM connector. I will try to connect these pins to the respective signals and see if it works.

Thanks

Johnny

Re: AW32 problems in 5V

JohnnyS2K — Sat, 05 Jul 2008 04:58:24 GMT

Worked !!! If I connect the pins VSSAD, VDDAD, VREFL and VREFH to the respective signals the MCU works properly in 5V. Funny, in 3,3V these pins can be left unconnected without problems...

Thanks

Johnny