Need technical support in operating MC9S12XEG128CAL microcontroller at 3.3V voltage level

[pavithrac]

Recently we migrated from HC12 (MC912DG128C) microcontroller to HCS12 (MC9S12XEG128CAL).

Checked the datasheet of MC9S12XEG128CAL controller and found that, this particular controller can also operate at 3.3V voltage level.

Currently we are using 5V power supply. Planned to migrate to 3.3V.

Please let me know whether this change will affect performance ?

[danielmartynek]

Hi

Regardless of the voltage level, in simple-chip mode the MCU bus frequency can be set up to 50 MHz and so the performance of the core and peripherals is not affected.

In expanded mode, however, the maximal internal bus frequency (at 3.3V) is reduced to 25 MHz, as you can see in Table A-30 in the RM.

Regarding ADC, you can measure in range of 0-5V if VDDA = VRH = 5V and run the MCU at 3.3V (VDDR = VDDX = 3.3V). See Table A-15. ATD Operating Characteristics.

Regards

Daniel