MPC5746C : Stop mode entry

[neojung]

Hello Sir,

During testing STOP mode entry/exit on MPC5746C(Maskset : 1N06M), I found that device can't enter to STOP mode when a SPI channel is configured as slave.

===> Here is failure mode...

DSPI_2.MCR.R = 0x00010001;
DSPI_2.MODE.CTAR_SLAVE[0].R = 0x38000000;

MC_ME.MCTL.R = 0xA0005AF0; /* Enter STOP mode and key */
MC_ME.MCTL.R = 0xA000A50F; /* Enter STOP mode and inverted key */
while (MC_ME.GS.B.S_MTRANS) {} /* Wait for STOP mode transition to complete */ ==> stuck at here

===> I found a workaround...

DSPI_2.MCR.R = 0x00010001;
DSPI_2.MODE.CTAR_SLAVE[0].R = 0x38000000;

DSPI_2.MCR.R = 0x80010001; /////////////////////////////////////////////////////////workaround

MC_ME.MCTL.R = 0xA0005AF0; /* Enter STOP mode and key */
MC_ME.MCTL.R = 0xA000A50F; /* Enter STOP mode and inverted key */
while (MC_ME.GS.B.S_MTRANS) {} /* Wait for STOP mode transition to complete */

Anyway, I found a workaround and it was reconfigure it's mode as SPI master.

Is this phenomenon is expected working?

Hope to receive any feedback!

Best regards,

Neo

[martin_kovar]

Hi Neo,

I tested this use case with MPC5775K and the behavior is the same. I had searched reference manual, but I did not find any notice about switching (D)SPI to master mode when you want to switch micro to stop mode.

When I have more time, I will try to investigate this behavior deeper and eventually contact application engineers and them about this point.

Regards,

Martin