I encountered a problem with MC13224 integrated on a board.
All was OK (RF, UART communication...) since the board turned off (the LED controled by the micro switched of). I checked power supplies. I then tried to reload the program into the micro but I got two types of error message :
"TCK (pin 9) low, but should be high. Please check target hardware" and "target VCC failure. Please check target voltage. Could not find supported CPU core on JTAG chain"
"Could not find supported CPU core on JTAG chain
Bad Jtag communication: Write to IR: Expected 0x1, got 0x0 (TAP Command : 2)
@ Off 0x5.
Unable to halt ARM core"
I sent an email to technical support. I have been told that the micro might be in Low Power Mode. I read the datasheet to get information about this mode and I learnt that there are only software ways to entry this mode: DOZE or HIB bits in SLEEP_SYNC should be set. I checked and they are both to zero. Thus, I am not really sure the micro is in Low Power Mode. Maybe another way exist (?)
Furthermore, this problem appeared on several boards but not on all. I then compared crystal signals from a safe board and from the dead one. These signals are the same.
Does someone can help me ? Many thanks.