/* * Copyright (c) 2022 Thomas Stranger * * SPDX-License-Identifier: Apache-2.0 */ &usart1_tx_pc4 { /* * enable open-drain drive such that no external push-pull to * open-drain converter is required. An external pull-up resistor * with approximately R=5k resistance is suggested. * Also a fixture connecting tx and rx pin is needed. */ drive-open-drain; bias-pull-up; };