USART2 Error in SmartCard mode

[panpb]

Posted on June 15, 2011 at 12:51

hi,

   I used STM32F217ZG for my new project, and cofigure USART2 as SmartCard mode, the source code showed as following:

&sharpdefine SAM_CLK_FREQ              (uint32_t)5000000

&sharpdefine SAMCARD_USART            USART2 &sharpdefine SAMCARD_USART_CLK   RCC_APB1Periph_USART2

&sharpdefine SAMCARD_IO_PIN                    GPIO_Pin_2

&sharpdefine SAMCARD_IO_GPIO_PORT       GPIOA &sharpdefine SAMCARD_IO_GPIO_CLK           RCC_AHB1Periph_GPIOA &sharpdefine SAMCARD_IO_SOURCE               GPIO_PinSource2 &sharpdefine SAMCARD_IO_AF                        GPIO_AF_USART2

&sharpdefine SAMCARD_CLK_PIN                    GPIO_Pin_7

&sharpdefine SAMCARD_CLK_GPIO_PORT      GPIOD &sharpdefine SAMCARD_CLK_GPIO_CLK          RCC_AHB1Periph_GPIOD &sharpdefine SAMCARD_CLK_SOURCE           GPIO_PinSource7 &sharpdefine SAMCARD_CLK_AF                    GPIO_AF_USART2 void samcard_hw_init(void) {  GPIO_InitTypeDef GPIO_InitStructure;   RCC_ClocksTypeDef Sys_RCC_Clocks;

 RCC_GetClocksFreq(&Sys_RCC_Clocks);

 RCC_AHB1PeriphClockCmd( SAMCARD_IO_GPIO_CLK   |  SAMCARD_CLK_GPIO_CLK,ENABLE);  RCC_APB1PeriphClockCmd(SAMCARD_USART_CLK,ENABLE);   USART_DeInit(SAMCARD_USART);    /* Configure USART CK alternate function push-pull */  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;  GPIO_InitStructure.GPIO_Pin = SAMCARD_CLK_PIN;  GPIO_Init(SAMCARD_CLK_GPIO_PORT, &GPIO_InitStructure);

 /* Configure USART Tx pin as alternate function open-drain */

 GPIO_InitStructure.GPIO_Pin = SAMCARD_IO_PIN;  GPIO_InitStructure.GPIO_OType = GPIO_OType_OD;  GPIO_Init(SAMCARD_IO_GPIO_PORT, &GPIO_InitStructure);

 /* Connect PA2 to USART2_TX */

 GPIO_PinAFConfig(SAMCARD_IO_GPIO_PORT, SAMCARD_IO_SOURCE, SAMCARD_IO_AF);

 /* Connect PD7 to USART2_CK */

 GPIO_PinAFConfig(SAMCARD_CLK_GPIO_PORT, SAMCARD_CLK_SOURCE, SAMCARD_CLK_AF);

 /* SC_USART configuration ----------------------------------------------------*/

 /* SC_USART configured as follow:  - Word Length = 9 Bits  - 1.5 Stop Bit  - Even parity  - BaudRate = 8064 baud  - Hardware flow control disabled (RTS and CTS signals)  - Tx and Rx enabled  - USART Clock enabled  */   /* USART Clock set to 5 MHz (PCLK1 (30 MHz) / 6) */    USART_SetPrescaler(SAMCARD_USART,Sys_RCC_Clocks.PCLK1_Frequency/(2*SAM_CLK_FREQ));     /* USART Guard Time set to 16 Bit */  USART_SetGuardTime(SAMCARD_USART, 16);

 SAM_USART_ClockInitStructure.USART_Clock = USART_Clock_Enable;

 SAM_USART_ClockInitStructure.USART_CPOL = USART_CPOL_Low;  SAM_USART_ClockInitStructure.USART_CPHA = USART_CPHA_1Edge;  SAM_USART_ClockInitStructure.USART_LastBit = USART_LastBit_Enable;  USART_ClockInit(SAMCARD_USART, &SAM_USART_ClockInitStructure);

 SAM_USART_InitStructure.USART_BaudRate = (SAM_CLK_FREQ+186)/372;

 SAM_USART_InitStructure.USART_WordLength = USART_WordLength_9b;  SAM_USART_InitStructure.USART_StopBits = USART_StopBits_1_5;  SAM_USART_InitStructure.USART_Parity = USART_Parity_Even;  SAM_USART_InitStructure.USART_Mode = USART_Mode_Rx|USART_Mode_Tx;  SAM_USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;  USART_Init(SAMCARD_USART, &SAM_USART_InitStructure);    /* Disable the SC_USART Parity Error Interrupt */  USART_ITConfig(SAMCARD_USART, USART_IT_PE, DISABLE);  /* Disable the SC_USART Framing Error Interrupt */  USART_ITConfig(SAMCARD_USART, USART_IT_ERR, DISABLE);  /* Disable the SC_USART Receive Not Empty Interrupt */  USART_ITConfig(SAMCARD_USART, USART_IT_RXNE, DISABLE);  /* Disable the SC_USART Transmitter Buffer Empty Interrupt */  USART_ITConfig(SAMCARD_USART, USART_IT_TXE, DISABLE);  /* Disable the SC_USART Transmitter Complete Interrupt */  USART_ITConfig(SAMCARD_USART, USART_IT_TC, DISABLE);  /* Disable the SC_USART OverRun Interrupt */  USART_ITConfig(SAMCARD_USART, USART_IT_ORE, DISABLE);  /* Enable SC_USART */  USART_Cmd(SAMCARD_USART, ENABLE);  USART_SmartCardNACKCmd(SAMCARD_USART,DISABLE);  /* Enable the Smartcard Interface */  USART_SmartCardCmd(SAMCARD_USART, ENABLE);  } The CPU system clock is 120MHz, and USART2 clock is 30MHz. after samcard_hw_init() be called, the SmartCard clock from PD7(USART2 CK pin) is measured by DPO, the smartcard clock is only 80Hz, not be 5MHz. I do not what happened or any error in my code, anyone can help me? thanks  a lot. #stm32f217zg-version-'y'-usart2-smartcard