topic Re: LPC546xx unused ISP pins in LPC Microcontrollers

LPC546xx unused ISP pins

terence_kong — Wed, 06 Nov 2019 00:20:16 GMT

Hi NXP,

I would like to know if In System Programming is not used, do we need to external pull high those ISP pins (ISP0-ISP2)?

Or we can just leave them floating?

Thanks in advance.

Re: LPC546xx unused ISP pins

ZhangJennie — Thu, 07 Nov 2019 06:05:13 GMT

terence K

To have your board secure designed， I suggest you set all unused ISP pin as high externally, to have a pull up resistor on those pins.

If you see the demo board schematic, you would find that those ISP pins are floating. As I know some of customers' board can still work normally even those pins are floating. But we also have minority customers meet problem.

So I suggest you have all unused ISP pins set to 1 externally to guarantee the board ISP design function well.

Have a great day,
Jun Zhang

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Re: LPC546xx unused ISP pins

terence_kong — Thu, 07 Nov 2019 16:44:44 GMT

Thanks Jun

Re: LPC546xx unused ISP pins

ZhangJennie — Fri, 08 Nov 2019 02:43:50 GMT

welcome.

Have a great day,
Jun Zhang

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