The following watchdogs are used to
monitor that the various blocks of the DLPC231S-Q1 are
properly operating. This is critical to ensuring that the LED brightness levels and
timings are being properly controlled.
- [SM_29] TPS99000S-Q1 Clock Ratio Monitor: The TPS99000S-Q1 calculates the ratio between its internal clock and the
external DLPC231S-Q1 clock input in order to validate
proper frequency operation of the main DLPC231S-Q1
clock source. The DLPC231S-Q1 main application
periodically reads this ratio. If the ratio is outside of the expected range,
the test fails. Upon failure an error is logged.
- [SM_30] DLPC231S-Q1 Processor Watchdog (WD1): The TPS99000S-Q1 monitors the DLPC231S-Q1
processor to make sure that it is continuously operating. The main application
software periodically resets the watchdog timer within an allocated time window.
If the watchdog signal is not received by the TPS99000S-Q1 during the time window, the test fails. Upon failure, the
TPS99000S-Q1 will signal a park of the DMD and
reset the chipset. The main application will read the reset cause from the TPS99000S-Q1 and assert HOST_IRQ during reset
initialization.
- [SM_31] DLPC231S-Q1 Sequencer Watchdog (WD2): The TPS99000S-Q1 monitors the SEQ_START signal that is generated by the
sequencer at the beginning of each frame. If the signal is not received within
approximately 7 frames, the TPS99000S-Q1 determines
that the sequencer is not functioning properly. The TPS99000S-Q1 alerts the DLPC231S-Q1. The DLPC231S-Q1 will attempt to disable and re-enable the
sequencer 3 times. If it is unsuccessful after 3 tries, and emergency shutdown
will be executed and an error will be logged.
- [SM_32] Sequencer Instruction
Read Watchdog: During proper operation, the sequencer block constantly
reads and executes instructions from the sequencer memory. The main application
software sets a timer within which an instruction must be read from memory. The
timer is reset every time an instruction is read. If an instruction is not read
within the allocated time, the test fails. Upon failure, emergency shutdown will
be executed and an error will be logged. This test is always active when an
image is being displayed.
- [SM_12] DMD Reset Instruction
Watchdog: Checks that the DMD has accepted command to update mirror
positions. A reset command from the DLPC231S-Q1 tells
the DMD to update mirror positions. If this command is not executed, mirrors
will remain in their current position. Upon successfully receiving a reset
command the DMD returns an acknowledge message. If this is not received by the
DLPC231S-Q1 within an acceptable time, this test
fails. Upon failure, emergency shutdown will be executed and an error will be
logged. This test is always active when an image is being displayed.