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Board Bring-Up with an LS1046

Question asked by Fabian Wunn on Mar 21, 2017
Latest reply on Mar 22, 2017 by Fabian Wunn

Hello all together,


I would be very glad if anyone could share his experience on the Power On Reset (POR) of the LS1046. I work as an electronics engineer and try to bring up a newly designed PCB featuring the LS1046. The issue is as follows:


After I Power Up the Device (See POR Signals Screenshot 1 - All Voltages are o.k and stable) I issue a POR by manually pulling PORESET to 0 (See Screenshot 2). Approximately 43 seconds later, the LS1046 issues a RESET Request and seems to be hung up. During the 43 seconds, I can only read the Device ID via JTAG. I can not connect to the core or see any registers. The LS1046 seems to be hung up in an early stage of its POR routine. 


  • First: Start Up the PCB, see Screenshot 1
  • Second: Issue PORESET manually, see Screenshot 2
  • Third: After 43s, RES_REQ is low and any device connection is refused, no Screenshot.


I can not explain the behavior and have made other observations regarding the state the device is in after issuing PORESET:

After Issuing a manual PORESET, I would expect the device to look for the RCW (Reset Configuration Word) while the pre-boot-loader is active. I tried to find out, if the LS1046 Pre-Boot-Loader looks for the RCW by setting the config source to SD-Card and checking on the SD Card CLOCK (from the device). The CLOCK does not occur and the LS1046 does not seem to get into the pre-boot-loarder state to fetch the RCW. 


How can I correctly bring up the LS1046?


I am glad for any of your ideas.