topic unused pins , output-mode disable pull-down? in LPC Microcontrollers

unused pins , output-mode disable pull-down?

jun1 — Tue, 19 Mar 2019 00:26:24 GMT

Hello.
In the LPC82X data sheet, it is recommended to disable unused pins and output LOW in the output mode, but is it also possible to disable pull-down?
The MODE bit in the IOCON register is
0x0 Inactive (no pull-down / pull-up resistor enabled).
0x1 Pull-down resistor enabled.
0x2 Pull-up resistor enabled.
0x3 Repeater
So, which one is recommended, 0x0 or 0x01?
Sorry, I do not have much knowledge of hardware.

Re: unused pins , output-mode disable pull-down?

ZhangJennie — Tue, 19 Mar 2019 09:02:04 GMT

Hi Jun

Make the unused pin as floating, and then set it as output low in software. GPIO output with pull-up disabled, and pull-down enabled.

Have a great day,
Jun Zhang

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Re: unused pins , output-mode disable pull-down?

jun1 — Tue, 19 Mar 2019 23:26:27 GMT

Thank you for a polite answer.
I understand that.

Have a nice day!

jun

Re: unused pins , output-mode disable pull-down?

ZhangJennie — Wed, 20 Mar 2019 02:27:36 GMT

You are welcome!