Greetings,

Is this your first attempt to enter debug on this chip? Or has this setup worked in the past?

Reset escalation occurs when the chip has seen too many resets since the last time the board was power-cycled. This is why the message to power cycle the board shows up and you must do this. If power cycling the board does not resolve the issue, then you need to figure out why the reset is happening so often and so quickly. Please check for any external watchdog or system bus chip on the board that may be triggering this. Use an oscilloscope on the RESET line to see what is happening.


Takao

This is first attempt to enter debug on this chip. When processor is reseting reset pin has stable 4.94-4.97V. As i understand reset pin should change voltage while processor is resetting. I use external power for pcb.
Tried raise reset pin from pcb , but after this device is uknown with cyclone LC or ID is  0000000. 

Hard to find reset line on PCB from other side, complicated PCB itself.

 http://i.piccy.info/i9/194b2b2e4b053bbe1ff0aa5efd6d8fed/1611000366/1118477/1407400/IMG_20210117_214412224_kopyia_kopyia.jpg

Can somebody tell wich pin number is JCOMP in LQFP 176 devices  :
  MPC5748G
• MPC5747G
• MPC5746G
• MPC5748C
• MPC5747C
Thanks.

Greetings,

Are you measuring reset with an oscilloscope? Could you send me screen captures of the scope signals so I can see what is going on with RESET and potentially other signals like TDI and TDO?

JCOMP is not necessary and we don't use it.


Takao

Greetings,

Have you made any progress?


Takao

Greetings,

The voltage dropping to 0 is not good. You should not see that at all unless you are manually power cycling the board or the cyclone has control over power. Check the schematic of the board and see if there is a current-limiting resistor on VDD and remove it. The cyclone requires some current to be able to get a voltage reference.


Takao

Greetings,

You should never use the cyclone to provide power for PowerPC Nexus devices. PPCNEXUS devices require the whole board to be powered up to function correctly, and the 5V and 0.2A is not enough to power up the whole board.

Power the board externally, and you need to find out what is causing the power to drop. This is the main problem you have and you will never enter debug mode if the chip is powered off when you attempt with our tools.


Takao

Greetings,

You must have VCC/VDD and GND both connected no matter the power setup. These are required connections. VDD is required as a voltage reference when the PEmicro hardware is not providing power to target. Use the 12V external power and have VCC (from the chip) connected to VDD on the Pemicro tool. You should be reading 5V with roughly 0.1A with this setup and you should have better success.

Once you have the right setup, then monitor RESET again and you should now see RESET toggle correctly. You should see at least 1 toggle, but too many toggles can trigger reset escalation. The behavior on this signal will be key to determining the problem.


Takao

Greetings.
Was able to see reset escalation with oscilloscope.
There are first 2 mouse clicks on video where we can see signals how cyclone trying connect to target (while connecting cyclone recognise target ID), 3rd mouse click - i shoted down nexus sofware cause of reset escalation fault, then after this processor is in periodical resetting state, where we can see sygnal of this reset.
This is automotive front body control module, where we have too many components on PCB and reset pin track is tricky hide, hard to find where this reset pin track goes.
Which element can cause such problem ?

https://www.youtube.com/watch?v=kLfPDSe1kHM&feature=youtu.be

Greetings.
After desolder one chip , which uses internal WTD and it's reset pin is same like target's reset pin (same track), i have some progress, but not till the end. Software still shows reset escalation fault (with desoldered chip), but one time from near 10 times connections it shows choosing algorithm window (which never was before). When i choose target device algorithm i stuck with no comunnication fault. Such closed circle i have now. Can be mpc5748 censored ? Which type of spc processor does ID 00000082 belong ? 

http://i.piccy.info/i9/711ae236f80dc7474d4b9165b49b0bb1/1613752115/738979/1407400/43366151570476_145780097366475_43060819592276799_n.jpg

http://i.piccy.info/i9/a09b90648470237d523e87cfc8d79836/1613752137/635029/1407400/50171151388161_862760604652575_5155087469441120582_n.jpg

Greetings,

ID of $0082 indicates a device within the MPC574xG family, which looks right.
Monitor the reset line again and make sure nothing else is interrupting communication. One in 10 times indicates you simply lucked out one chance but by the time you selected your algorithm the reset has toggled so many times that you are going to reach reset escalation again. Something on reset is toggling too many times.


Takao

Should i search only RESET track line, or other signals as well can be under reset influence like tdo,tms,tck,tdi, +5V ?

Greetings,

For now, just check RESET and see the behavior as you attempt to enter debug and load the algorithm. Only if RESET signal only has at most 2 pulses should you then move onto TDI and TDO and TCK to see if maybe those signals are not behaving well (should have sharp rising edge, no RC-like curve, not much noise).


Takao

still trying to read this mpc5748 
i lifted all 5 pins from pcb tms,tdo,tck,tdi,rst thought would be luck but 
problem still the same - target in reset escalation and even hear quiet sound
when processor is being reseted. In datasheet there is no pinout for this qfp176 pin processor. Which pin can be used in this reseting process else ?