1.8V 8 pin lowest cost processor (S08QA)

[carlnormansuret]

Hi Guys,

I did a design with the SO8QA2 processor, everything was fine until i realise the low voltage reset is ON during boot up, so if you run a 1.8V regulator it will not always boot depending on 1.7V or 1.81V. The processor runs down fine at 1.6V, but i cant get it to boot because of SPMSC1 LVDRE (low voltage reset enable). If this bit was OFF during boot, i could disable it and i would be fine, but its not, so this processor seems to be useless at 1.8V.

Any suggestions on getting this processor to work? Or, another very low cost processor similar that will do the job? (has to be about USD$0.50, 70c max).

The application is a very very low power (100uA) external watch dog, it just checks 2 pins are toggling and sets an output if they are not for 1 second, VERY simple external watch dog.

[vicentegomez]

Is there a way that you boot at more than 1.8 V?

Unfortunately in all the S08 family the PMSC1 LVDRE is enable by reset.

There are other device, not 8 bit devices that can boot at 1.8 V like the kinetis L family but are not in 8 pins package.

Please let me know if you nee more information about the kinetis family 

ARM Cortex-M0+|Ultra-Low Power Kinetis KL0x MCUs|NXP 

Regards

Vicente

[vicentegomez]

Also you can check the LPC824 family 

LPC824M201JHI33|Cortex-M+|Low Cost 32-bit MCU|NXP 

Regards

[carlnormansuret]

Thanks, I ended up going with MKL03Z8VFG4, seems very cheap, its overkill for what we want, but its cheap so thats fine.

[vicentegomez]

Please let us know if you need more information for the kinetis L family

Regards

Vicente Gomez