User Manual
227
Rev. 1.1
2019-03-18
TLE984xQX
Microcontroller with LIN and Power Switches for Automotive Applications
System Control Unit - Power Modules (SCU-PM)
Figure 39 Block diagram of CGU including Clock Watchdogs
8.3.1.1
Functional Description of Clock Watchdog Module
The clock watchdog module consists of a counter. This counter monitors the number of system clocks within
a defined time window. The duration of the time window is defined by a clock (
LP_CLK
), which is independent
from the monitored system clock (
MI_CLK
). If the required number of clock cycles is not reached within this
time window an clock watchdog NMI will be issued.
In case the clock watchdog NMI will be issued, indicating that the clock is not within the required frequency
range, then the user has different options to overcome this situation:
• stay on mi_clk but reconfigure PLL to re-gain the required clock frequency. This would be the most time
consuming measure to avoid emergency shutdown of the above listed modules.
• switch to divider factors 2, 3 and 4 to try to come back to specified frequency range.
• switch to LP_CLK, which also can be divided by factor 2, 3 and 4. This is the fastest option which allows the
user to operate with a well defined backup clock rate. After this has been done the user can start
investigating the root cause of the issued clock watchdog NMI, while operating on
LP_CLK
.
The register chapter below includes all necessary flags for setting up the analog module clock and monitoring
its status during operation.
Clock Watchdog (SCU_PM)
SCU_PM
SCU_DM
CLK WDT2
CLK WDT1
CLK WDT3
fsys
TFILT _CLK
MI_CLK
APCLK1_DIV
{1,2,3,4}
APCLK1_DIV
APCLK2_DIV
APCLK2_DIV
Analog Modules
MU
LIN
LS
HS
SCU_PM
{1,2,3,4}
SCUPM_AMCLK_TH_HYS.
AMCLK2_UP_TH
SCUPM_AMCLK_TH_HYS.
AMCLK2_LOW_TH
SCUPM_AMCLK_TH_HYS.
AMCLK1_UP_TH
SCUPM_AMCLK_TH_HYS.
AMCLK2_LOW_TH