LPC802 | flashing PINs via SWD

[shai_b]

Dear team,

Could you please confirm that if my customer would like to program our LPC802 MCU he needs to use the pin numbers 4-(RST) ,6 -(SWCLK),7-(SWDIO):

Does the schematics above is correct or something is missing?

Wating for your king feedback, Thanks in advance

Regards,

Shai

[DanielRuvalcaba]

Hi,

According to the LPC802 User Manual, this is the way to connect the SWD pins:

Please just keep in mind the pull-up/pull-down resistors and the ISP entry.

For more information you can take a look at chapter 25 of the LPC802 User Manual.

Regards, Daniel.

[shai_b]

@DanielRuvalcaba ,

Thanks for your input, could you please advise if ISP is mandatory for SWD?

According the DS the relevant pins are Swdclk, swdio, and vcc + ground.

Also, can you please advise what is requirements for running code read protection (CRP) feature?

Wait for your kind feedback, thanks in advance.

Regards,

Shai

[DanielRuvalcaba]

Hi,

The ISP entry can be used to recover some of the configurations that disable the SWD port, e.g. CRP.

Please, take a look to Table 6 of the LPC802 User Manual (available in here).

So ISP is not strictly mandatory but if you are planning to use the CRP, it might be recommended to keep the ISP pin.

Also, please take a look to this article. It is about some design considerations that can be helpful for you.

https://community.nxp.com/t5/LPCXpresso-IDE-FAQs/Design-Considerations-for-Debug/m-p/469565

I hope this helps, Daniel.

[shai_b]

Dear @DanielRuvalcaba,

Thanks for your input, can you please be more specific regards the CRP process.

The customer would like to know if he needs to lock the device from reading the flash.
Can it be done only with the SWD interface (2 pins without the need of using ISP at all)?

Waiting for your kind feedback, Many Thanks.

Regards,

Shai

[DanielRuvalcaba]

Hi,

Yes, it is possible using only SWDIO and SWCLK, but please keep in mind that if you don’t have a pull-up resistor in the ISP pin, then the first time you flash the MCU, it might enter ISP mode. Once you apply the CRP, this should not happen anymore.

If you do have that pull-up resistor, then it won’t enter ISP mode that first time.

I hope this helps, Daniel.

[coolxiangm]

Hi Daniel,

Do you have any chance to take look at my post? I've post my question yesterday, but no one responds.

The link is https://community.nxp.com/t5/LPC-Microcontrollers/OM13066-Reprogram-LPC11U24-via-USB/m-p/1474655#M49...

Thanks,

Frank