[nuttx] branch master updated: esp32xx: Workaround to avoid printing serial trash character

[pkarashchenko]

This is an automated email from the ASF dual-hosted git repository.

pkarashchenko pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/nuttx.git


The following commit(s) were added to refs/heads/master by this push:
     new 694e6f550b esp32xx: Workaround to avoid printing serial trash character
694e6f550b is described below

commit 694e6f550b2d84f8dfb280e70b5f61fd0df19eaa
Author: Alan Carvalho de Assis <acas...@gmail.com>
AuthorDate: Thu May 11 16:14:46 2023 -0300

    esp32xx: Workaround to avoid printing serial trash character
    
    During the serial reconfiguration from bootloader to the
    NuttX a trash character "?" (Unicode replacement U+FFFD)
    was printed in the screen.
    
    This fix was discovered by Sylvio Alves from Espressif!
---
 arch/risc-v/src/esp32c3/esp32c3_lowputc.c | 6 ++++++
 arch/xtensa/src/esp32/esp32_serial.c      | 5 +++++
 arch/xtensa/src/esp32s2/esp32s2_lowputc.c | 6 ++++++
 arch/xtensa/src/esp32s3/esp32s3_lowputc.c | 6 ++++++
 4 files changed, 23 insertions(+)

diff --git a/arch/risc-v/src/esp32c3/esp32c3_lowputc.c 
b/arch/risc-v/src/esp32c3/esp32c3_lowputc.c
index 90574ed940..5fc1d6a546 100644
--- a/arch/risc-v/src/esp32c3/esp32c3_lowputc.c
+++ b/arch/risc-v/src/esp32c3/esp32c3_lowputc.c
@@ -766,6 +766,12 @@ void esp32c3_lowputc_config_pins(const struct 
esp32c3_uart_s *priv)
 {
   /* Configure the pins */
 
+  /* Keep TX pin in high level to avoid "?" trash character
+   * This "?" is the Unicode replacement character (U+FFFD)
+   */
+
+  esp32c3_gpiowrite(priv->txpin, true);
+
   esp32c3_gpio_matrix_out(priv->txpin, priv->txsig, 0, 0);
   esp32c3_configgpio(priv->txpin, OUTPUT_FUNCTION_1);
 
diff --git a/arch/xtensa/src/esp32/esp32_serial.c 
b/arch/xtensa/src/esp32/esp32_serial.c
index 5d6b587bb7..ed497f48fc 100644
--- a/arch/xtensa/src/esp32/esp32_serial.c
+++ b/arch/xtensa/src/esp32/esp32_serial.c
@@ -1885,6 +1885,11 @@ static void esp32_config_pins(struct esp32_dev_s *priv)
    * But only one GPIO pad can connect with input signal
    */
 
+  /* Keep TX pin in high level to avoid "?" trash character
+   * This "?" is the Unicode replacement character (U+FFFD)
+   */
+
+  esp32_gpiowrite(priv->config->txpin, true);
   esp32_configgpio(priv->config->txpin, OUTPUT_FUNCTION_3);
   esp32_gpio_matrix_out(priv->config->txpin, priv->config->txsig, 0, 0);
 
diff --git a/arch/xtensa/src/esp32s2/esp32s2_lowputc.c 
b/arch/xtensa/src/esp32s2/esp32s2_lowputc.c
index 6ac310fb8b..3674b64ce9 100644
--- a/arch/xtensa/src/esp32s2/esp32s2_lowputc.c
+++ b/arch/xtensa/src/esp32s2/esp32s2_lowputc.c
@@ -683,6 +683,12 @@ void esp32s2_lowputc_config_pins(const struct 
esp32s2_uart_s *priv)
 {
   /* Configure the pins */
 
+  /* Keep TX pin in high level to avoid "?" trash character
+   * This "?" is the Unicode replacement character (U+FFFD)
+   */
+
+  esp32s2_gpiowrite(priv->txpin, true);
+
   /* Route UART TX signal to the selected TX pin */
 
   esp32s2_gpio_matrix_out(priv->txpin, priv->txsig, 0, 0);
diff --git a/arch/xtensa/src/esp32s3/esp32s3_lowputc.c 
b/arch/xtensa/src/esp32s3/esp32s3_lowputc.c
index a2bec80622..334ce2e1d3 100644
--- a/arch/xtensa/src/esp32s3/esp32s3_lowputc.c
+++ b/arch/xtensa/src/esp32s3/esp32s3_lowputc.c
@@ -795,6 +795,12 @@ void esp32s3_lowputc_config_pins(const struct 
esp32s3_uart_s *priv)
 {
   /* Configure the pins */
 
+  /* Keep TX pin in high level to avoid "?" trash character
+   * This "?" is the Unicode replacement character (U+FFFD)
+   */
+
+  esp32s3_gpiowrite(priv->txpin, true);
+
   if (uart_is_iomux(priv))
     {
       esp32s3_configgpio(priv->txpin, OUTPUT_FUNCTION_1);