Part Number: TMS320C6711D
Dear TI support team,
I am submitting this help request as the problem we are facing with TMS320C6711D is similar to the one reported in the Thread "TMS320C6711D: DSP not responsive after a period of inactivity".
We have a board mounting a 5962-9866101VXA DSP, an EEPROM where the BOOT Software reside and an FPGA which handles the DSP and EEPROM Reset signals (released when all the supplies are stable).
Most of the times the board boots fine but after long periods of inactivity (i.e. 3 weeks) we see the DSP fails the boot procedures. Once the BOOT procedure fails, the board remains in this bad state and even powering it ON/OFF for several times seems not having an effect, the BOOT keeps failing.
We deiced to start the investigation probing the DSP supplies [1.85V and +3V3] to double check their levels and sequencing at power on. As soon as we probed the supplies during power-on the DSP started working again, performing the boot regularly. Several Power-ON/OFF confirmed the DSP always boots fine without any issue.
We want to perform additional measurements to understand the root cause of the problem, in particular focusing on the EEPROM signals. So far we can confirm the FPGA is working correctly and the EEPROM reset is released 300uS before the DSP Reset is released. Unfortunately these measurements were taken after the unit started working again.
As the issue seems to be highlighted when the unit is left off for several weeks, we performed a test to see if the misbehavior of the unit might be influenced by any on-board supplies residual charge. With unit off, we tried using a 10K resistor at the input/output of the board DCDCs and connect them to GND for a few seconds. The test didn’t give any additional info as at start-up the unit performed the Boot without problems.
The flight unit will be unavailable for a few days and we wanted to collect ideas for a well structured investigation plan. In particular based on your experience:
- Any idea on how to accelerate the failing process without hardware modifications?
- Any idea on the possible root cause or how to narrow it down?
Any suggestion would be more than appreciated.
Thank you,
Regards
Enrico
