From d8ede4fbf03bb484d84ced5ce3a2f5c582c4e6a3 Mon Sep 17 00:00:00 2001
From: Giovanni Di Sirio <gdisirio@gmail.com>
Date: Sat, 26 May 2018 16:39:05 +0000
Subject: Fixed bug #951.

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@12054 110e8d01-0319-4d1e-a829-52ad28d1bb01
---
 os/hal/ports/STM32/LLD/USARTv1/hal_serial_lld.c | 12 ++++++++++--
 os/hal/ports/STM32/LLD/USARTv1/hal_uart_lld.c   | 12 ++++++++++--
 os/hal/ports/STM32/LLD/USARTv2/hal_serial_lld.c | 17 +++++++++++++----
 os/hal/ports/STM32/LLD/USARTv2/hal_uart_lld.c   | 10 +++++++++-
 4 files changed, 42 insertions(+), 9 deletions(-)

(limited to 'os/hal')

diff --git a/os/hal/ports/STM32/LLD/USARTv1/hal_serial_lld.c b/os/hal/ports/STM32/LLD/USARTv1/hal_serial_lld.c
index 6b837356a..17d08b7a3 100644
--- a/os/hal/ports/STM32/LLD/USARTv1/hal_serial_lld.c
+++ b/os/hal/ports/STM32/LLD/USARTv1/hal_serial_lld.c
@@ -99,6 +99,7 @@ static const SerialConfig default_config =
  * @param[in] config    the architecture-dependent serial driver configuration
  */
 static void usart_init(SerialDriver *sdp, const SerialConfig *config) {
+  uint32_t fck;
   USART_TypeDef *u = sdp->usart;
 
   /* Baud rate setting.*/
@@ -107,9 +108,16 @@ static void usart_init(SerialDriver *sdp, const SerialConfig *config) {
 #else
   if (sdp->usart == USART1)
 #endif
-    u->BRR = STM32_PCLK2 / config->speed;
+    fck = STM32_PCLK2 / config->speed;
   else
-    u->BRR = STM32_PCLK1 / config->speed;
+    fck = STM32_PCLK1 / config->speed;
+
+  /* Correcting USARTDIV when oversampling by 8 instead of 16.
+     Fraction is still 4 bits wide, but only lower 3 bits used.
+     Mantissa is doubled, but Fraction is left the same.*/
+  if (config->cr1 & USART_CR1_OVER8)
+    fck = ((fck & ~7) * 2) | (fck & 7);
+  u->BRR = fck;
 
   /* Note that some bits are enforced.*/
   u->CR2 = config->cr2 | USART_CR2_LBDIE;
diff --git a/os/hal/ports/STM32/LLD/USARTv1/hal_uart_lld.c b/os/hal/ports/STM32/LLD/USARTv1/hal_uart_lld.c
index 3242e1478..c10944226 100644
--- a/os/hal/ports/STM32/LLD/USARTv1/hal_uart_lld.c
+++ b/os/hal/ports/STM32/LLD/USARTv1/hal_uart_lld.c
@@ -196,6 +196,7 @@ static void usart_stop(UARTDriver *uartp) {
  * @param[in] uartp     pointer to the @p UARTDriver object
  */
 static void usart_start(UARTDriver *uartp) {
+  uint32_t fck;
   uint16_t cr1;
   USART_TypeDef *u = uartp->usart;
 
@@ -208,9 +209,16 @@ static void usart_start(UARTDriver *uartp) {
 #else
   if (uartp->usart == USART1)
 #endif
-    u->BRR = STM32_PCLK2 / uartp->config->speed;
+    fck = STM32_PCLK2 / uartp->config->speed;
   else
-    u->BRR = STM32_PCLK1 / uartp->config->speed;
+    fck = STM32_PCLK1 / uartp->config->speed;
+
+  /* Correcting USARTDIV when oversampling by 8 instead of 16.
+     Fraction is still 4 bits wide, but only lower 3 bits used.
+     Mantissa is doubled, but Fraction is left the same.*/
+  if (uartp->config->cr1 & USART_CR1_OVER8)
+    fck = ((fck & ~7) * 2) | (fck & 7);
+  u->BRR = fck;
 
   /* Resetting eventual pending status flags.*/
   (void)u->SR;  /* SR reset step 1.*/
diff --git a/os/hal/ports/STM32/LLD/USARTv2/hal_serial_lld.c b/os/hal/ports/STM32/LLD/USARTv2/hal_serial_lld.c
index 4b5f20836..e4d521bd7 100644
--- a/os/hal/ports/STM32/LLD/USARTv2/hal_serial_lld.c
+++ b/os/hal/ports/STM32/LLD/USARTv2/hal_serial_lld.c
@@ -213,17 +213,26 @@ static uint8_t sd_out_buflp1[STM32_SERIAL_LPUART1_OUT_BUF_SIZE];
  * @param[in] config    the architecture-dependent serial driver configuration
  */
 static void usart_init(SerialDriver *sdp, const SerialConfig *config) {
+  uint32_t fck;
   USART_TypeDef *u = sdp->usart;
 
   /* Baud rate setting.*/
 #if STM32_SERIAL_USE_LPUART1
-  if ( sdp == &LPSD1 )
-  {
-      u->BRR = (uint32_t)( ( (uint64_t)sdp->clock * 256 ) / config->speed);
+  if ( sdp == &LPSD1 ) {
+    fck = (uint32_t)(((uint64_t)sdp->clock * 256 ) / config->speed);
   }
   else
 #endif
-  u->BRR = (uint32_t)(sdp->clock / config->speed);
+  {
+    fck = (uint32_t)(sdp->clock / config->speed);
+  }
+
+  /* Correcting USARTDIV when oversampling by 8 instead of 16.
+     Fraction is still 4 bits wide, but only lower 3 bits used.
+     Mantissa is doubled, but Fraction is left the same.*/
+  if (config->cr1 & USART_CR1_OVER8)
+    fck = ((fck & ~7) * 2) | (fck & 7);
+  u->BRR = fck;
 
   /* Note that some bits are enforced.*/
   u->CR2 = config->cr2 | USART_CR2_LBDIE;
diff --git a/os/hal/ports/STM32/LLD/USARTv2/hal_uart_lld.c b/os/hal/ports/STM32/LLD/USARTv2/hal_uart_lld.c
index 62624b50d..1c4cafd81 100644
--- a/os/hal/ports/STM32/LLD/USARTv2/hal_uart_lld.c
+++ b/os/hal/ports/STM32/LLD/USARTv2/hal_uart_lld.c
@@ -252,6 +252,7 @@ static void usart_stop(UARTDriver *uartp) {
  * @param[in] uartp     pointer to the @p UARTDriver object
  */
 static void usart_start(UARTDriver *uartp) {
+  uint32_t fck;
   uint32_t cr1;
   const uint32_t tmo = uartp->config->timeout;
   USART_TypeDef *u = uartp->usart;
@@ -260,7 +261,14 @@ static void usart_start(UARTDriver *uartp) {
   usart_stop(uartp);
 
   /* Baud rate setting.*/
-  u->BRR = (uint32_t)(uartp->clock / uartp->config->speed);
+  fck = (uint32_t)(uartp->clock / uartp->config->speed);
+
+  /* Correcting USARTDIV when oversampling by 8 instead of 16.
+     Fraction is still 4 bits wide, but only lower 3 bits used.
+     Mantissa is doubled, but Fraction is left the same.*/
+  if (uartp->config->cr1 & USART_CR1_OVER8)
+    fck = ((fck & ~7) * 2) | (fck & 7);
+  u->BRR = fck;
 
   /* Resetting eventual pending status flags.*/
   u->ICR = 0xFFFFFFFFU;
-- 
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