From 2b6aabd1ea4476650c08e5080ddaee2ee03ae38b Mon Sep 17 00:00:00 2001
From: Rodrigo Garcia <Rodrigo.Garcia@espressif.com>
Date: Wed, 15 Dec 2021 02:22:59 -0300
Subject: [PATCH] Forces UART Flush() to wait until all bits are sent

---
 cores/esp32/esp32-hal-uart.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/cores/esp32/esp32-hal-uart.c b/cores/esp32/esp32-hal-uart.c
index c3f2df37207..b76d02f18f8 100644
--- a/cores/esp32/esp32-hal-uart.c
+++ b/cores/esp32/esp32-hal-uart.c
@@ -140,6 +140,9 @@ uart_t* uartBegin(uint8_t uart_nr, uint32_t baudrate, uint32_t config, int8_t rx
         ESP_ERROR_CHECK(uart_set_line_inverse(uart_nr, UART_SIGNAL_TXD_INV | UART_SIGNAL_RXD_INV));    
     }
 
+    // Set RS485 half duplex mode on UART.  This shall force flush to wait up to sending all bits out
+    ESP_ERROR_CHECK(uart_set_mode(uart_nr, UART_MODE_RS485_HALF_DUPLEX));
+
     UART_MUTEX_UNLOCK();
 
     uartFlush(uart);