Hello, I am working in mdk5. For my application I am writting code for RS485. While debugging I found that my FCR register is not loading its value. The code I have written is show below. void uart_rs485(void) { SCU_PinConfigure(2,3, SCU_CFG_MODE_FUNC2);// p2_3 for U3_TXD SCU_PinConfigure(2,4, SCU_CFG_MODE_FUNC2);// p2_4 for U3_RXD GPIO_SetDir(4,11,GPIO_DIR_OUTPUT);// Set GIO_B1_RS485_DIR as output
LPC_USART3->LCR = 0x83;// Line Control Register LPC_USART3->FCR =0x07;//FIFO buffer LPC_USART3->FDR =0;// Fractional Divide LPC_USART3->DLM =0;//Divide Latch MSB LPC_USART3->DLL =98;//Divide Latch LSB LPC_USART3->LCR =0x03;//Disable DLAB
} void uart_rs485_transmit(void) { GPIO_PinWrite(4,11,1);//Making Transmit Enable high if(LPC_USART3->LSR & 0x20) { LPC_USART3->THR = 83; } }
void uart_rs485_receive(void) { GPIO_PinWrite(4,11,0);//Receive Enable a = LPC_USART3->RBR; } Please help me in this flow. Thank you in advance
Hi Dharmaraj, Thanks a lot.I will check that link you have shared.
Hi Dharmaraj, I have gone through all the sample codes given. But I didnt get any match codes for UART communication. USB and I2C coomunications are similar to RS485?
Hi all, While dealing with UART1 of LPC1857 to be used as RS232 I have coded as below. For providing clock:
void SCI_PortClock (uint32_t clock) { if (clock) { LPC_CCU1->CLK_M3_UART1_CFG |= 3; while (!(LPC_CCU1->CLK_M3_UART1_STAT & 1)); } else { LPC_CCU1->CLK_M3_UART1_CFG &= ~(3); while (LPC_CCU1->CLK_M3_UART1_STAT & 1); } }
Pin configuration and UART configuration:
RS232 PINS U1_TXD = P3_4 U1_RXD = P3_5 */ const PIN_ID RS232_PIN[] = { { RTE_UART1_RX_PORT, RTE_UART1_RX_BIT, (RTE_UART1_RX_FUNC | SCU_SFS_EZI)}, { RTE_UART1_TX_PORT, RTE_UART1_TX_BIT, (RTE_UART1_TX_FUNC)} }; void uart_sci(void) { const PIN_ID *pin; SCI_PortClock (1); for (pin = RS232_PIN; pin != &RS232_PIN[sizeof(RS232_PIN)/sizeof(PIN_ID)]; pin++) { if (pin->port == 0x10) { SCU_CLK_PinConfigure (pin->num, pin->config_val); continue; } SCU_PinConfigure(pin->port, pin->num, pin->config_val); } LPC_UART1->LCR = 0x83; //Line Control Register LPC_UART1->FDR = 0; //Fractional Divide LPC_UART1->DLM = 0; //Divide Latch MSB LPC_UART1->DLL = 98; //Divide Latch LSB LPC_UART1->LCR = 0x03; //Disable DLAB LPC_UART1->FCR = 0x07; //FIFO buffer } void uart_sci_transmit(void) { if(LPC_UART1->LSR & 0x20) { LPC_UART1->THR = 83; } } void uart_sci_receive(void) { a = LPC_UART1->RBR; }
While debugging, I came to know that FCR, DLL, DLM are not configured as I have given. Transmission and reception is unsuccessful. LCR is loaded properly. Inviting your valuable suggestions. I am using Keil MDK5.