S12X256SV - low power mode with SPI running

[nithin]

Hello,

We work for the automotive projects around the world. We are using the controller S12X256SV in the Engine Control Unit(ECU) for various automotive applications. Now we have a special requirement for blinking a bulb connected in dashboard.

To realize this requirement, S12X256SV should communicate with an external device(driver circuit which will drive the bulb) through SPI in low power mode. We need low power mode because the ECU and the driver IC will be ON for more than two days continuously, and in some cases the battery rating is limited.

As per the s12x user manual, I didn't get any solution to implement this(SPI in low power mode).

1) Does this controller hardware supports low power mode with SPI running?

2) And what will be the power usage of S12X256SV in normal mode and in low power mode ?

Regards,

Nithin

[DPB]

Hello

1) The S12X device feature WAIT and STOP low power modes.

During STOP and WAIT modes the SPI operation is limited to handling transfers that are already in progress when STOP or WAIT mode is entered. See Reference Manual SPI section x.4.7.2 and x.4.7.3. This is to help maintain synchronization with external devices.

To achieve low power typically a device would spend most of the time in WAIT or STOP mode and then enter RUN mode to carry out tasks like SPI transmissions. When the tasks are complete the device would then re-enter WAIT or STOP. So although the SPI does not continue to operate fully in STOP or WAIT mode, it is still possible to achieve low power by lowering the RUN mode duty cycle.

2)The WAIT and STOP mode current consumption is listed in the reference manual electrical sections....

S12X256SV does not exist. It looks like there is a letter missing between X and 2. Which device do you mean?

DPB