MPC860 PIT problem

[abdellahhadj-ra]

Hello colleagues,

I use the Periodic Interrupt Timer of the MP860 with the EXTCLK source and a Prescaler of 512 ( MODCK [1:2] =10).

When the power supply 3V3 of the MPC860 rises sharply (7 to 10 ms), the Timer Interrupt is correctly generated and the main program is executed correctly.

When the power supply 3V3 of the MPC860 rises slowly (30 to 40 ms), the Timer Interrupt is never generated but the main program is executed correctly. It's as if the internal clock PITRTCLK isn't generated in the chip.

The exact reference of the MPC860 is MPC860DEVR80D4 with  a date code of  September 2011.

Has anyone heard of dysfunctions of the PIT depending of the slope of the 3V3 power supply ?

I check the MPC860 datasheet and I didn't find any specifications about the slope of the 3V3 power supply. 

Best regards. 

[alexander_yakov]

The Periodic Interrupt Timer may be stopped by Freeze (FRZ) signal, which is used to freeze several device timers, when the device enters debug mode. This is useful to prevent these timers from overflow and cause unexpected interrupt, when the core is stopped in debug mode.

Please check the value of PISCR[PITF] bit, if this bit is set to "1" than please clear this bit to "0" and check if the problem appears when this bit cleared. Please look MPC860 User Manual, Table 10-24 for more information.