K60 UART Pullup

johnaraujo — Fri, 25 Jan 2019 21:53:10 GMT

We are using the K60FN1M0VLQ12. I want to use the internal pullups on UART4_RX (pin 119) and UART2_RX (pin 129). Will the pullups remain enable even when we configure these pins for the UART ALT3 functions? Thank!

Re: K60 UART Pullup

mjbcswitzerland — Fri, 25 Jan 2019 23:32:58 GMT

Hi John

Yes, pull-ups are valid for the UART input functions.

In the uTasker project it is done with

_CONFIG_PERIPHERAL(D, 2, (PD_2_UART2_RX | UART_PULL_UPS)); // UART2_RX on PD2 (alt. function 3)

and
_CONFIG_PERIPHERAL(C, 14, (PC_14_UART4_RX | UART_PULL_UPS)); // UART4_RX on PC14 (alt. function 3)

Otherwise you just need to set the PORTD_PCR2 and PORTC_PCR14 registers to have their ALT fields set to 3 and their pulls polarity and enable to 0x03.

Pull-ups on the UART inputs ensures that they don't float in low power modes, which can otherwise cause higher than expected current consumption.

Regards

Mark

Complete K60 solutions, training and support:http://www.utasker.com/kinetis.html
Kinetis K60:
- http://www.utasker.com/kinetis/TWR-K60N512.html
- http://www.utasker.com/kinetis/TWR-K60D100M.html
- http://www.utasker.com/kinetis/TWR-K60F120M.html
- http://www.utasker.com/kinetis/ELZET80_NET-KBED.html
- http://www.utasker.com/kinetis/ELZET80_NET-K60.html

topic Re: K60 UART Pullup in Kinetis Microcontrollers

K60 UART Pullup

Re: K60 UART Pullup