Jernej SLO
Newbie level 2
Hi!
Few days ago our production faced a problem when downloading firmware to a TMS320LF2406APZS processor through RS232 connection. 100 devices were planed to be programmed, but 3 of them showed a locked FLASH memory and could't be programmed. All devices were new. Similar problem sometimes showed up in development phase when using JTAG programming, but never at first time programming.
We also tried to program before mentioned 3 faulty devices with JTAG interface, but the result was the same as with RS232 programming - processor's FLASH was locked and it couldn't be programmed. The usual unlock code didn't work. During any programming phase there was no power loss.
Is this some kind of a silicon bug? Did it hapen to someone else? Can it be caused by a bad PCB design / power supply design? Maybe exists an important power-up sequence of supply voltages that must be followed (5V FLASH programming supply and 3.3V logic supply)? When the processors with locked FLASH were replaced with new ones, everything worked OK.
Best regards,
Jernej Skvarc
Few days ago our production faced a problem when downloading firmware to a TMS320LF2406APZS processor through RS232 connection. 100 devices were planed to be programmed, but 3 of them showed a locked FLASH memory and could't be programmed. All devices were new. Similar problem sometimes showed up in development phase when using JTAG programming, but never at first time programming.
We also tried to program before mentioned 3 faulty devices with JTAG interface, but the result was the same as with RS232 programming - processor's FLASH was locked and it couldn't be programmed. The usual unlock code didn't work. During any programming phase there was no power loss.
Is this some kind of a silicon bug? Did it hapen to someone else? Can it be caused by a bad PCB design / power supply design? Maybe exists an important power-up sequence of supply voltages that must be followed (5V FLASH programming supply and 3.3V logic supply)? When the processors with locked FLASH were replaced with new ones, everything worked OK.
Best regards,
Jernej Skvarc