S12XE & 3.3V supply

[Eric_t]

Hi,

I have a board that uses a S12XE controller and the power supply is 5V.

It has also an atmel flash memory that works at 3.3V

I have to redesign and simplify the board.

Since to board has already power supply of 3.3V, I am thinking of making S12XE controller to work at 3.3V.

The only problem I have is that the specification gives as minimum voltage of VDDR, VDDA 3.13 that is very close to 3.3V (the difference is only 170mV). For the reset I am going to use LM37XX that keeps uC to reset at the voltage of 3.14V

I would like to ask if anyone have already used any HCS controller at 3.3V and if he believe that is save to used power supply so close to minimum voltage.

Thank you.

[danielmartynek]

Hi,

It shouldn’t be a problem. The MCU has Low Voltage Reset (LVR) which forces the device to reset if input voltage is too low, protecting against brown-out condition. LVR assert level is typically 3.02V, deassert at 3.13V (max) see Table A-21.

Evaluation board DEVKIT-S12XE uses 3.3V power supply.

Regards,

Daniel