In our design we have used OMAPL138EZWTD4 Processor.In production lot out of 130 boards we have observed booting issues on 8 boards at first time power ON .
- Observation on First time Power ON booting issue : 6 Boards
On 6 boards at initial power ON the board is not booting at all, we have checked OMAPL138 reads boot code from NAND Flash, loads kernel
and the application successfully but there is no print messages on console. On applying second power ON or Manual reset, the same action happens and there is print messages on console.After reset or second power on we have check all the functionality and are working properly without any issues.This issue seems to be inconsistency and unpredictable when we will observe booting failure at first power on those faulty 6 boards.
- Booting occurs only on Manual reset : 2 Boards
On 2 boards even on second power ON there is no print messages on console.On applying Manual reset only, the same action happens and there is print messages on console.The same issue observed on long back and reported to TI support team FYR service request with reference number #1-994465421. When we changed the processor on one of the reset issue board then it's booting at first time power on, we have checked for consistency found to be OK.
Work around :
- Checked power ON sequence --- OK
- Checked timing between IO power and Reset --- 210ms
- Increased and reduced the timing --- no improvement
- Checked the Boot mode pins latching wrt reset --- OK
- Checked the Nand Flash Chip select,RE# and R/B# found to be OK
- As per silicon errata recommended provided strong pull up and pull down resistors and even tried with hard-coded (without boot switch on faulty boards).
Kindly let me know your inputs / suggestions at the earliest to find the root cause of this issue