1/* 2 * Copyright (c) 2022 Thomas Stranger 3 * 4 * SPDX-License-Identifier: Apache-2.0 5 */ 6 7&usart1_tx_pc4 { 8 /* 9 * enable open-drain drive such that no external push-pull to 10 * open-drain converter is required. An external pull-up resistor 11 * with approximately R=5k resistance is suggested. 12 * Also a fixture connecting tx and rx pin is needed. 13 */ 14 drive-open-drain; 15 bias-pull-up; 16}; 17