How I can disconnect OpenSDA debug module on FRDM-KL05Z?

[OmarIsaiPinales]

I remove R28 to disconnect the debugging module, but the microcontroller does not work. And if I put the J5 jummper works fine.

I need to disconnect the debugging module to consume less current.

[Hui_Ma]

Hi,

I do a test with FRDM-KL05Z board, the KL05 will work with R28 removed and jumper J4 be shuttled (J5 jumper is open).

For the OpenSDA K20 chip pin6 VREGIN connects with OPENSDA USB VBUS, P3V3_USBSER will with 1.5V voltage.

I recommend customer to use external DC power supply, add 3.3v to jumper 4 and short J9-3 with J9-4.

The reason is for RST_TGTMCU pin connects with K20's pin21, which default function is ADC0_SE9.

The ADC input pin as voltage divide resistor and KL05 reset pin voltage will divide to 1.3V and KL05 will be in reset state.

So short J9-3 and J9-4 will pull up the KL05 reset pin to 3.3V and KL05 could work.

Wish it helps.

Have a great day,
best regards,

Ma Hui

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