Whether BKGD signal pin On S08 and S12 series MCU need to add pull resistance?

[jinhuiwu]

Whether BKGD signal pin On S08 and S12 series  MCU  need to add pull resistance?

[vicentegomez]

Hi Jinhui

In the S08 case there is not necessary a pull up resistor on the BKGD pin, regarding to the S12 I believe also is not necessary but I am not expert on S12, you can ask on the S12 community

Regards

Vicente Gomez

[jinhuiwu]

I see！Thanks  for answer！

By the way.I can't program flash.

After identifying,BKGD pin was pulled low.

What causes the BKGD pins to be pulled low?

[vicentegomez]

maybe the pin is set as a GPIO, please check if you can the BKGDPE = 1

If a debug system is connected to the 6-pin standard background debug header, it can hold BKGD/MS low during a POR or immediately after issuing a background debug force reset, which forces the MCU to active background mode.

Please also check the signal on the reset pin.