STM32F103ZE USART baud rate over 115200

[galczys]

Posted on July 29, 2011 at 14:10

Hi,

I have a

little problem

with setting

a custom

speed on the

STM32

above

115200th

The problem occurs

both when

using the

init

or

manual configuration

(manual

calculation

of values ??for

the registry

BRR)

.

There is no problem

with different

transmissions

9600

, 28800

until

115200th

After

this value,

the terminal

is silent.

Only

by using the

library function

to initialize the

USART

to the terminal

reached

some

wrong information.

With

manual configuration

did not

reach

above the

115200th

Overall,

I must

dispel

USART

to

1Mb

, because

I make

the

servo

controller

which

is at

such a

speed

that

communicates with the

interface.

I would add

that I am using

win 7

and

the

terminal

v1.9b

.

Once

I tested the

speed

, eg

256 000

for

ATMega32

and

worked

without a problem

.

&sharpinclude ''stm32f10x.h''

&sharpinclude ''stm32f10x_conf.h''

 

void

RCC_Conf

(

void

)

;

 

int

main

(

)

{

RCC_Conf

(

)

;

uint16_t

zmienna

=

0

;

  USART_InitTypeDef USART_InitStructure

;

GPIO_InitTypeDef GPIO_InitStructure

;

  RCC_APB2PeriphClockCmd

(

RCC_APB2Periph_USART1

|

RCC_APB2Periph_GPIOA, ENABLE

)

;

 

/* Configure USART1 Tx (PA.09) as alternate function push-pull */

GPIO_InitStructure.

GPIO_Pin

=

GPIO_Pin_9

;

GPIO_InitStructure.

GPIO_Mode

=

GPIO_Mode_AF_PP

;

GPIO_InitStructure.

GPIO_Speed

=

GPIO_Speed_50MHz

;

GPIO_Init

(

GPIOA,

&

GPIO_InitStructure

)

;

 

/* Configure USART1 Rx (PA.10) as input floating */

GPIO_InitStructure.

GPIO_Pin

=

GPIO_Pin_10

;

GPIO_InitStructure.

GPIO_Mode

=

GPIO_Mode_IN_FLOATING

;

GPIO_Init

(

GPIOA,

&

GPIO_InitStructure

)

;

    USART_ClockInitTypeDef USART_ClockInitStructure

;

  USART_ClockInitStructure.

USART_Clock

=

USART_Clock_Disable

;

USART_ClockInitStructure.

USART_CPOL

=

USART_CPOL_Low

;

USART_ClockInitStructure.

USART_CPHA

=

USART_CPHA_2Edge

;

USART_ClockInitStructure.

USART_LastBit

=

USART_LastBit_Disable

;

  USART_ClockInit

(

USART1,

&

USART_ClockInitStructure

)

;

   USART_InitStructure.

USART_WordLength

=

USART_WordLength_8b

;

USART_InitStructure.

USART_StopBits

=

USART_StopBits_1

;

USART_InitStructure.

USART_Parity

=

USART_Parity_No

;

USART_InitStructure.

USART_HardwareFlowControl

=

USART_HardwareFlowControl_None

;

USART_InitStructure.

USART_Mode

=

USART_Mode_Rx

|

USART_Mode_Tx

;

 

uint32_t

tmp

;

  tmp

=

USART1

-

>

CR1

;

tmp

|

=

USART_InitStructure.

USART_WordLength

|

USART_InitStructure.

USART_Parity

|

USART_InitStructure.

USART_Mode

;

USART1

-

>

CR1

=

tmp

;

  tmp

=

USART1

-

>

CR2

;

tmp

|

=

USART_InitStructure.

USART_StopBits

;

USART1

-

>

CR2

=

tmp

;

  tmp

=

USART1

-

>

CR3

;

tmp

|

=

USART_InitStructure.

USART_HardwareFlowControl

;

USART1

-

>

CR3

=

tmp

;

  USART1

-

>

BRR

=

(

uint16_t

)

0x9c4

;

 

/* Enable USART1 */

USART_Cmd

(

USART1, ENABLE

)

;

 

while

(

1

)

{

while

(

USART_GetFlagStatus

(

USART1, USART_FLAG_TXE

)

==

RESET

)

{

}

USART_SendData

(

USART1,

0xA2

)

;

while

(

USART_GetFlagStatus

(

USART1, USART_FLAG_RXNE

)

==

RESET

)

{

}

zmienna

=

USART_ReceiveData

(

USART1

)

;

}

 

return

0

;

}

 

void

RCC_Conf

(

void

)

{

ErrorStatus HSEStartStatus

;

 

//reset ustawie? RCC

RCC_DeInit

(

)

;

 

//W??cz HSE

RCC_HSEConfig

(

RCC_HSE_ON

)

;

 

//Czekaj a? HSE b?dzie gotowy

HSEStartStatus

=

RCC_WaitForHSEStartUp

(

)

;

 

if

(

HSEStartStatus

==

SUCCESS

)

{

FLASH_PrefetchBufferCmd

(

FLASH_PrefetchBuffer_Enable

)

;

 

//zwloka dla pamieci Flash

FLASH_SetLatency

(

FLASH_Latency_2

)

;

 

//HCLK = SYSCLK

RCC_HCLKConfig

(

RCC_SYSCLK_Div1

)

;

 

//PCLK2 = HCLK

RCC_PCLK2Config

(

RCC_HCLK_Div1

)

;

 

//PCLK1 = HCLK/2

RCC_PCLK1Config

(

RCC_HCLK_Div2

)

;

 

//PLLCLK = 8MHz * 9 = 72MHz

RCC_PLLConfig

(

RCC_PLLSource_HSE_Div1, RCC_PLLMul_9

)

;

 

//W??cz PLL

RCC_PLLCmd

(

ENABLE

)

;

 

//Czekaj a? PLL poprawnie si? uruchomi

while

(

RCC_GetFlagStatus

(

RCC_FLAG_PLLRDY

)

==

RESET

)

{

}

 

//PLL b?dzie zrodlem sygnalu zegarowego

RCC_SYSCLKConfig

(

RCC_SYSCLKSource_PLLCLK

)

;

 

while

(

RCC_GetSYSCLKSource

(

)

!

=

0x08

)

{

}

}

   

}

#stm32-usart

[Tesla DeLorean]

Posted on July 29, 2011 at 17:56

The 24 MHz VL Discovery has NO problem outputting at 460800 baud into a USB-to-CMOS Serial dongle.

a) Check your serial port supports the rate. Most internal/motherboard ones don't. b) Attach a scope and verify the bit/baud clocking is what you expect. c) RS232 driver chips often filter >1Mbaud. void RCC_Configuration(void); void GPIO_Configuration(void); void USART_Configuration(void); void RCC_Configuration(void) {     ErrorStatus HSEStartUpStatus;   /* Enable HSE */   RCC_HSEConfig(RCC_HSE_ON);   /* Wait till HSE is ready */   HSEStartUpStatus = RCC_WaitForHSEStartUp();   if (HSEStartUpStatus == SUCCESS)   { #if 0 // VL Does not require     /* Enable Prefetch Buffer */     FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable);     /* Flash 0 wait state */     FLASH_SetLatency(FLASH_Latency_0); #endif     /* HCLK = SYSCLK */     RCC_HCLKConfig(RCC_SYSCLK_Div1);     /* PCLK2 = HCLK */     RCC_PCLK2Config(RCC_HCLK_Div1);     /* PCLK1 = HCLK */     RCC_PCLK1Config(RCC_HCLK_Div1);     /* ADCCLK = PCLK2/4 */     RCC_ADCCLKConfig(RCC_PCLK2_Div4);     /* PLLCLK = 8MHz * 3 = 24 MHz */     RCC_PLLConfig(RCC_PLLSource_HSE_Div1, RCC_PLLMul_3);     /* Enable PLL */     RCC_PLLCmd(ENABLE);     /* Wait till PLL is ready */     while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET);     /* Select PLL as system clock source */     RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);     /* Wait till PLL is used as system clock source */     while(RCC_GetSYSCLKSource() != 0x08);     } } void USART_Configuration(void) {     GPIO_InitTypeDef GPIO_InitStructure;   USART_InitTypeDef USART_InitStructure;   RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);   /* Configure USART Tx as alternate function push-pull */   GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;  // PA.09 USART1.TX   GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;   GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;   GPIO_Init(GPIOA, &GPIO_InitStructure);   /* Configure USART Rx as input floating */   GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10; // PA.10 USART1.RX   GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;   GPIO_Init(GPIOA, &GPIO_InitStructure);   /* USART resources configuration (Clock, GPIO pins and USART registers) ----*/   /* USART configured as follow:         - BaudRate = 460800 baud         - Word Length = 8 Bits         - One Stop Bit         - No parity         - Hardware flow control disabled (RTS and CTS signals)         - Receive and transmit enabled   */   USART_InitStructure.USART_BaudRate = 460800;   USART_InitStructure.USART_WordLength = USART_WordLength_8b;   USART_InitStructure.USART_StopBits = USART_StopBits_1;   USART_InitStructure.USART_Parity = USART_Parity_No;   USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;   USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;   /* Enable UART clock */   RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);   /* USART configuration */   USART_Init(USART1, &USART_InitStructure);   /* Enable the USART1 */   USART_Cmd(USART1, ENABLE); } int main(void) {     char str[] = ''Welcome to wherever you are...'';     char *s;   RCC_Configuration();   USART_Configuration();   /* Infinite loop */     while(1)     {         s = str;         while(*s)       {         while((USART1->SR & 0x40)==0);         USART1->DR = *s++;       }     }   /* does not exit - kind of important */   return(1); }