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I am using a NUCLEO-L476RG development board,
I am learning to write GPIO drivers for STM32 family
I have implementing a simple logic in which I need to turn on an LED when a push button is pressed.
I have a strange issue:
Edit 1:The Bread board LED turns ON when the line temp=10 is commented, it doesn't turn ON when the delay issue called. Assuming if I add any line of code into that while loop the LED does not turn ON
The Bread board LED turns ON when the delay() function is commented, it doesn't turn ON when the delay issue called.
What could be the issue?
I have powered the board using the mini usb connector on the board, and the clock is configured at MSI with 4MHz
#define delay() for(uint32_t i=0; i<=50000; i++);
int main(void)
{
GPIO_Handle_t NucleoUserLED,NucleoUserPB,BreadBoardLED,BreadBoardPB;
uint8_t inputVal,BBinpVal;
uint32_t temp;
//User green led in the nucleo board connected to PA5
NucleoUserLED.pGPIO = GPIOA;
NucleoUserLED.GPIO_Pin_Cfg.GPIO_PinNumber = GPIO_PIN_5;
NucleoUserLED.GPIO_Pin_Cfg.GPIO_PinMode = GPIO_MODE_OP;
NucleoUserLED.GPIO_Pin_Cfg.GPIO_PinPuPdControl = GPIO_IP_NO_PUPD;
NucleoUserLED.GPIO_Pin_Cfg.GPIO_PinOpType = GPIO_OP_TYPE_PP;
//User blue button in the nucleo connected to PC13
NucleoUserPB.pGPIO = GPIOC;
NucleoUserPB.GPIO_Pin_Cfg.GPIO_PinNumber = GPIO_PIN_13;
NucleoUserPB.GPIO_Pin_Cfg.GPIO_PinMode = GPIO_MODE_IP;
NucleoUserPB.GPIO_Pin_Cfg.GPIO_PinPuPdControl = GPIO_IP_NO_PUPD;
//User led in the bread board connected to PC8
BreadBoardLED.pGPIO = GPIOC;
BreadBoardLED.GPIO_Pin_Cfg.GPIO_PinNumber = GPIO_PIN_8;
BreadBoardLED.GPIO_Pin_Cfg.GPIO_PinMode = GPIO_MODE_OP;
BreadBoardLED.GPIO_Pin_Cfg.GPIO_PinPuPdControl = GPIO_IP_NO_PUPD;
BreadBoardLED.GPIO_Pin_Cfg.GPIO_PinOpType = GPIO_OP_TYPE_PP;
//User DPDT connected in the breadboard connected to PC6
BreadBoardPB.pGPIO = GPIOC;
BreadBoardPB.GPIO_Pin_Cfg.GPIO_PinNumber = GPIO_PIN_6;
BreadBoardPB.GPIO_Pin_Cfg.GPIO_PinMode = GPIO_MODE_IP;
BreadBoardPB.GPIO_Pin_Cfg.GPIO_PinPuPdControl = GPIO_IP_PU;
GPIO_PeriClkCtrl(GPIOA, ENABLE);
GPIO_PeriClkCtrl(GPIOC, ENABLE);
GPIO_Init(&NucleoUserLED);
GPIO_Init(&NucleoUserPB);
GPIO_Init(&BreadBoardLED);
GPIO_Init(&BreadBoardPB);
while(1)
{
/*****************************************************************
* Controlling the IO present in the nucleo board *
*****************************************************************/
inputVal = GPIO_ReadInputPin(NucleoUserPB.pGPIO, NucleoUserPB.GPIO_Pin_Cfg.GPIO_PinNumber);
BBinpVal = GPIO_ReadInputPin(BreadBoardPB.pGPIO, BreadBoardPB.GPIO_Pin_Cfg.GPIO_PinNumber);
if(inputVal == 0)
{
GPIO_ToggleOutputPin(NucleoUserLED.pGPIO, NucleoUserLED.GPIO_Pin_Cfg.GPIO_PinNumber);
}
/*****************************************************************
* Controlling the IO present in the bread board *
*****************************************************************/
if (BBinpVal == 0 )
{
GPIO_WriteOutputPin(BreadBoardLED.pGPIO, BreadBoardLED.GPIO_Pin_Cfg.GPIO_PinNumber, 1);
}
else
{
GPIO_WriteOutputPin(BreadBoardLED.pGPIO, BreadBoardLED.GPIO_Pin_Cfg.GPIO_PinNumber, 0);
}
delay();
}
return 0;
}
It is not a function only the macrodefinition.
Your loop is likely to be optimized out
define it as
void inline __attribute__((always_inline)) delay(uint32_t delay)
{
while(delay--) __asm("");
}
Bear in mind that 50000 can be quite long if you run on low clock settings.
Not sure what the issue is because "it is not working" is not very specific.
However there are "quality" issues:
That is an inappropriate use of a macro - there is no benefit over using a function. The function call overhead argument does not hold - it is a delay, it is supposed to take time!
The empty-loop counter is not declared volatile - the compiler at any optimisation level other then the minimum is likely to remove the loop altogether.
A for-loop for a delay is a crude and generally non-deterministic solution, with a period that will change between compilers, with different compiler options and on different targets or with different clock speeds. STM32 is a Cortex-M device and given that you should use the SYSTICK counter for this. For example, as a minimum something like:
volatile uint32_t tick = 0 ;
void SysTick_Handler(void)
{
tick++ ;
}
void delayms( uint32_t millisec )
{
static bool init = false ;
if( !init )
{
SysTick_Config( SystemCoreClock / 1000 ) ;
init = true ;
}
uint32_t start = tick ;
while( tick - start < millisec ) ;
}
The issue was solved by declaring the iterator as a global variable. Now the LED turns on when the Push button is pressed
Previous implementation
#define delay() for(uint32_t i=0; i<=50000; i++);
Working implementation
uint32_t temp;
void delay(void)
{
for(temp = 0;temp<=50000;temp++)
{
;
}
}
Can any one tell me how declaring the variable as global solves the issue?
Find the working implementation below
#include <stdint.h>
#include "stm32l476xx.h"
#include "stm32l476xx_gpoi_driver.h"
#if !defined(__SOFT_FP__) && defined(__ARM_FP)
#warning "FPU is not initialized, but the project is compiling for an FPU. Please initialize the FPU before use."
#endif
uint32_t temp;
void delay(void)
{
for(temp = 0;temp<=50000;temp++)
{
;
}
}
int main(void)
{
GPIO_Handle_t NucleoUserLED,NucleoUserPB,BreadBoardLED,BreadBoardPB;
volatile uint8_t inputVal,BBinpVal;
//User green led in the nucleo board connected to PA5
NucleoUserLED.pGPIO = GPIOA;
NucleoUserLED.GPIO_Pin_Cfg.GPIO_PinNumber = GPIO_PIN_5;
NucleoUserLED.GPIO_Pin_Cfg.GPIO_PinMode = GPIO_MODE_OP;
NucleoUserLED.GPIO_Pin_Cfg.GPIO_PinPuPdControl = GPIO_IP_NO_PUPD;
NucleoUserLED.GPIO_Pin_Cfg.GPIO_PinOpType = GPIO_OP_TYPE_PP;
//User blue button in the nucleo connected to PC13
NucleoUserPB.pGPIO = GPIOC;
NucleoUserPB.GPIO_Pin_Cfg.GPIO_PinNumber = GPIO_PIN_13;
NucleoUserPB.GPIO_Pin_Cfg.GPIO_PinMode = GPIO_MODE_IP;
NucleoUserPB.GPIO_Pin_Cfg.GPIO_PinPuPdControl = GPIO_IP_NO_PUPD;
//User led in the bread board connected to PC8
BreadBoardLED.pGPIO = GPIOC;
BreadBoardLED.GPIO_Pin_Cfg.GPIO_PinNumber = GPIO_PIN_8;
BreadBoardLED.GPIO_Pin_Cfg.GPIO_PinMode = GPIO_MODE_OP;
BreadBoardLED.GPIO_Pin_Cfg.GPIO_PinPuPdControl = GPIO_IP_NO_PUPD;
BreadBoardLED.GPIO_Pin_Cfg.GPIO_PinOpType = GPIO_OP_TYPE_PP;
//User DPDT connected in the breadboard connected to PC6
BreadBoardPB.pGPIO = GPIOC;
BreadBoardPB.GPIO_Pin_Cfg.GPIO_PinNumber = GPIO_PIN_6;
BreadBoardPB.GPIO_Pin_Cfg.GPIO_PinMode = GPIO_MODE_IP;
BreadBoardPB.GPIO_Pin_Cfg.GPIO_PinPuPdControl = GPIO_IP_PU;
GPIO_PeriClkCtrl(GPIOA, ENABLE);
GPIO_PeriClkCtrl(GPIOC, ENABLE);
GPIO_Init(&NucleoUserLED);
GPIO_Init(&NucleoUserPB);
GPIO_Init(&BreadBoardLED);
GPIO_Init(&BreadBoardPB);
while(1)
{
/*****************************************************************
* Controlling the IO present in the nucleo board *
*****************************************************************/
inputVal = GPIO_ReadInputPin(NucleoUserPB.pGPIO, NucleoUserPB.GPIO_Pin_Cfg.GPIO_PinNumber);
BBinpVal = GPIO_ReadInputPin(BreadBoardPB.pGPIO, BreadBoardPB.GPIO_Pin_Cfg.GPIO_PinNumber);
if(inputVal == 0)
{
GPIO_ToggleOutputPin(NucleoUserLED.pGPIO, NucleoUserLED.GPIO_Pin_Cfg.GPIO_PinNumber);
}
/*****************************************************************
* Controlling the IO present in the bread board *
*****************************************************************/
temp = 10;
if (BBinpVal == 0 )
{
GPIO_WriteOutputPin(BreadBoardLED.pGPIO, BreadBoardLED.GPIO_Pin_Cfg.GPIO_PinNumber, 1);
}
else
{
GPIO_WriteOutputPin(BreadBoardLED.pGPIO, BreadBoardLED.GPIO_Pin_Cfg.GPIO_PinNumber, 0);
}
delay();
}
return 0;
}
The issue is solved,
There was an bug in the driver layer I have written
Whenever an GPIO is configured as Input, the registers related to Output for that GPIO pin should be set to their reset value or the driver should not implement the API related to the Output
I am trying to enable UART for STM32 Nucleo - F429ZI.
I have gone through user manual and it says by default USART 3 can be configured for virtual com port purpose. Here is my code. I can see that USART 3 has pins D8 and D9. Here is my code. What am I doing wrong here, I don't see prints on my com port.
Data sheet refered - https://www.st.com/resource/en/data_brief/nucleo-f429zi.pdf
https://www.st.com/resource/en/user_manual/dm00244518-stm32-nucleo-144-boards-stmicroelectronics.pdf
//test print msg
char usr_msg[256];
//Ends
void printmsg(char *msg)
{
for(uint32_t i = 0; i < strlen(msg); i++)
{
while(USART_GetFlagStatus(USART3, USART_FLAG_TXE) != SET);
USART_SendData(USART3, msg[i]);
}
}
static void prvSetupUart(void)
{
GPIO_InitTypeDef gpio_uart_pins;
USART_InitTypeDef uart3_init;
//GPIO D is connected to AHB1 bus.
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);
// Enable the UART 3 peripheral clock -- connected to APB1 bus.
RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3, ENABLE);
// zero the local variable
memset(&gpio_uart_pins,0,sizeof(gpio_uart_pins));
memset(&uart3_init,0,sizeof(uart3_init));
// GPIO port D - pin 8 like TX
// GPIO port D - ping 9 like RX
gpio_uart_pins.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_9;
gpio_uart_pins.GPIO_Mode = GPIO_Mode_AF; //AF - Alternate function i.e. TX and RX.
gpio_uart_pins.GPIO_PuPd = GPIO_PuPd_UP; //Pull up so that we see some default voltage.
GPIO_Init(GPIOD, &gpio_uart_pins);
uart3_init.USART_BaudRate = 115200;
uart3_init.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
uart3_init.USART_Mode = USART_Mode_Tx | USART_Mode_Rx;
uart3_init.USART_Parity = USART_Parity_No;
uart3_init.USART_StopBits = USART_StopBits_1;
uart3_init.USART_WordLength = USART_WordLength_8b;
USART_Init(USART3,&uart3_init);
//Enable USART 3 peripheral.
USART_Cmd(USART3, ENABLE);
}
int main(void)
{
//Step number 1 - DeInit the RCC - Reset Control Clock so that we don't use Pre-scaler or PLL.
// Basically, we want to use lower speed.
RCC_DeInit();
// update the System Core Clock
//Step number 2 -- Update the clock to use the default clock.
SystemCoreClockUpdate();
prvSetupUart();
sprintf(usr_msg, "This is Hello World\r\\n");
printmsg(usr_msg);
for(;;);
}
you forgot to set what AF mode to be used (there are possible 16 AF modes for every pin). At the moment AF registers are set to the 0 and it is wrong. You need to make it 7.
How can it be archived using the SPL library (depreciated and not supported anymore) I do not know.
Here is the register version
#define GPIO_AFRL_AFRL0_Msk (GPIO_AFRL_AFRL0_0 | GPIO_AFRL_AFRL0_1 | GPIO_AFRL_AFRL0_2 | GPIO_AFRL_AFRL0_3)
void GPIO_SetAF(GPIO_TypeDef *gpio, unsigned pin, unsigned AF)
{
volatile uint32_t *AFreg = &gpio -> AFR[pin >= 8];
if(AF <= 15)
{
if(pin > 7) pin -= 8;
*AFreg &= ~(GPIO_AFRL_AFRL0_Msk << (4 * pin));
*AFreg |= (AF << (4 * pin));
}
}
I am currently working for the first time with a PIC microcontroller. In the code I specified exactly which PIC, compiler, etc I am using. Maybe this is of help.
I am trying to set up UART communication on the PIC32 and send a hex code like 0x41 for example to a terminal on my computer through RS232. To convert the signal from the PIC UART to RS232 levels I am using a MAX232EPE.
At the moment I am running into the problem that when I send 0x41 for example from the PIC32 to the terminal or vice versa, the received data doesn't match. I think this being caused by a mistake in my baud rate settings, but I am not sure. Could someone please look over my code and see if someone can see a problem? Did I forget to define something? Did I define something wrong? Did I mis calculate the baud rate?
P.S. I know the data being received doesn't match the data send because i checked in the "watches" in debug mode in mplab and when I echo the data send from the terminal to the PIC32 back to the terminal it doesn't match either.
The Delay and interrupt code can be ignored, they are working as expected, so I really believe the problem has to do with the initial setting of the PIC/buad rate.
I hope this is clear enough, any help is very much appreciated
Thanks,
See code below
/*
The configuration below and in void UART1_Init should set up the UART correctly.
I want to achieve a buadrate of 9600. My external Crystal is 8MHz. So:
FPLLIDIV=2, FPLLMUL=20, FPLLODIV=1, FPBDIV=2, FNOSC=PRIPLL, BRGH = 0, and U1BRG = 259.
This should give me the desired baudrate of 9600.
- ((8MHz / 2) * 20)/2) = 40MHz PBclk.
- U1BRG = (PBclk/(16*Buad rate))-1 so 259
- 16*Buad rate because BRGH = 0
PIC32MX795F512H
MPLAB X IDE V3.26
XC32 Compiler
PICKit3
*/
#include <stdio.h>
#include <stdlib.h>
#include <xc.h>
#include <plib.h>
// Give useful names to pins
#define LED1_TRIS TRISDbits.TRISD6
#define LED1 LATDbits.LATD6
#define UART1TX_TRIS TRISDbits.TRISD3
#define UART1RX_TRIS TRISDbits.TRISD2
#define FOSC 8000000 // Crystal frequency = 8 MHz
#define SYS_FREQ (80000000UL) // SYSCLK is 80 MHz
#define GetSystemClock() (FOSC) // For delay
#pragma config FPLLIDIV=DIV_2 // PLL Input Divider Value (Divide by 2)
#pragma config FPLLMUL=MUL_20 // Phase-Locked Loop (PPL) muiltiplier, multiplier of 20
#pragma config FPLLODIV=DIV_1 // Postscaler for PLL, output divided by 1
#pragma config FPBDIV=DIV_2 // 2 = PBCLK is SYSCLK divided by 2 (80MHz/2 = 40MHz)
#pragma config FWDTEN=OFF // Watch Dog Timer (WDT) is not enabled. It can be enabled by software
#pragma config CP=OFF // Code-Protect, 1 = OFF/Disabled
#pragma config BWP=OFF // Boot Flash Write-protect, 1 = OFF/Disabled
#pragma config POSCMOD=XT // Primary oscillator configuration, HS = HS Oscillator mode selection
#pragma config FNOSC=PRIPLL // Oscillator selection, PRIPLL = Primary Oscillator with PLL module
#pragma config OSCIOFNC=OFF // CLKO output disabled
#pragma config FSOSCEN=OFF // Disable secondary Oscillator
int UART_RX_Count; // Counter variable for the UART1 receiver interrupt
int UART_TX_Count; // Counter varible for the UART1 transmitted interrupt
unsigned char RD_SER_NUM; // Variable to store command to read serial number
unsigned char UART_RX_OUTPUT; // Variable to store the UART output
unsigned char i;
void UART1_Init(void){
// UART1 initialization
U1MODEbits.ON = 1; // UART1 is enabled
U1MODEbits.SIDL = 0; // Continue operation in idle mode
U1MODEbits.IREN = 0; // Disable IrDA (IrDA Encoder and Decoder Enable bit)
U1MODEbits.RTSMD = 1; // !U1RTS! pin is in Simplex mode, 0 = !U1RTS! pin is in Flow Control mode
U1MODEbits.UEN = 0; // UxTX and UxRX pins are enabled and used; UxCTS and UxRTS/UxBCLK pins are controlled by corresponding bits in the PORTx register
U1MODEbits.WAKE = 1; // Enable Wake-up on Start bit Detect During Sleep Mode bit
U1MODEbits.LPBACK = 0; // UARTx Loopback Mode Select bit, 0 = disabled, loopback = UxTX output is internally connected to the UxRX input
U1MODEbits.PDSEL = 2; // Parity and Data Selection bits, 10 = 8-bit data, odd parity
U1MODEbits.STSEL = 0; // Stop Selection bit, 0 = 1 stop bit
U1MODEbits.BRGH = 0; // High Baud Rate Enable bit, 0 = Standard Speed mode 16x baud clock enabled
U1MODEbits.RXINV = 1; // Receive Polarity Inversion bit, 1 = UxRX Idle state is 0
U1STAbits.URXEN = 1; // 1 = UART1 receiver is enabled. U1RX pin is controlled by UARTx (if ON = 1)
U1STAbits.UTXEN = 1; // 1 = UART1 transmitter is enabled. U1TX pin is controlled by UARTx (if ON = 1)
U1STAbits.UTXINV = 1; // Transmit Polarity Inversion bit, 1 = UxTX Idle state is 0
U1STAbits.ADM_EN = 0; // 0 = Automatic Address Detect mode is disabled
U1BRG = 259; // Baud Rate Divisor bits (0-15 bits), set baud rate, 9600 # 40 MHz PBclk
__builtin_disable_interrupts(); // Tell CPU to stop paying attention to interrupts
INTCONbits.MVEC = 1; // Multi Vector interrupts
U1STAbits.URXISEL = 0; // 0x = Interrupt flag bit is set when a character is received
U1STAbits.UTXISEL = 1; // 01 = Interrupt flag bit is set when all characters have been transmitted
IPC6bits.U1IP = 5; // Set UART1 priority 5 of 7
IPC6bits.U1IS = 0; // Set UART1 sub priority to 0
IFS0bits.U1RXIF = 0; // Clear UART1 RX interrupt flag
IFS0bits.U1TXIF = 0; // Clear UART1 TX interrupt flag
IEC0bits.U1RXIE = 1; // Enable UART1 RX ISR
__builtin_enable_interrupts(); // Tell CPU to start paying attention to interrupts again
UART_RX_Count = 0; // Set initial UART1 received interrupts count to 0
UART_TX_Count = 0; // Set initial UART1 transmit interrupts count to 0
}
void __ISR(_UART_1_VECTOR, IPL5SRS) UART1_INT(void){
if(INTGetFlag(INT_U1RX)){ // Check if UART1 RX interrupt was triggered
LED1 = ~LED1; // Toggle LED1
UART_RX_Count++; // Add 1 to UART1 RX interrupt occurrence counter
// UART_RX_OUTPUT = U1RXREG; // Read UART1 RX buffer/register
U1TXREG = U1RXREG; // Transmit the received data back
// U1STAbits.OERR = 0; // Clear UART1 buffer overflow
IFS0bits.U1RXIF = 0; // Clear UART1 RX interrupt flag
}else{
if(INTGetFlag(INT_U1TX)){ // Check if UART1 TX interrupt was triggered
UART_TX_Count++; // Add 1 to UART1 TX interrupt occurrence counter
IEC0bits.U1TXIE = 0; // Disable UART1 TX ISR
IFS0bits.U1TXIF = 0; // Clear UART1 TX interrupt flag
}
}
}
// DelayMs creates a delay of given milliseconds using the Core Timer
void DelayMs(WORD delay){
unsigned int int_status;
while( delay-- ){
int_status = INTDisableInterrupts();
OpenCoreTimer(GetSystemClock() / 200);
INTRestoreInterrupts(int_status);
mCTClearIntFlag();
while( !mCTGetIntFlag() );
}
mCTClearIntFlag();
}
int main(){
UART1_Init(); // Call the initializations function of UART1
LED1_TRIS = 0; // Set the LED1 as an output
UART1TX_TRIS = 0; // Set UART1 TX pin as output
UART1RX_TRIS = 1; // Set UART1 RX pin as input
LED1 = 0; // Turn off LED1
while(1){
// DelayMs(1000);
// IEC0bits.U1TXIE = 1; // Enable UART1 TX ISR
// U1TXREG = 0x41; // Send command to U1TXREG
}
return 0;
}
As You are using PIC32MX795F512H, You can use the MPLAB Harmony framework tool for creating your project. So that you need not to play on bit level and stuck in minor error or most probabaly typo error.
Its convinient to generate drivers and all framework properly.
Thanks and regards
Ravi
Using Harmony will actually help you avoid simple errors like the one you have encountered. Especially for the clocks you even have auto calculating functions decreasing your implementation time significantly.
I'am using STM32F4 board with CMSIS library and I want setup an interrupt driven SPI, it means an interrupt is triggered each time a byte is sent by the SPI peripheral. The initiaisation function is as below:
void init_SPI1(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
GPIO_InitTypeDef GPIO_InitStruct;
SPI_InitTypeDef SPI_InitStruct;
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
GPIO_InitStruct.GPIO_Pin = GPIO_Pin_7 | GPIO_Pin_6 | GPIO_Pin_5|GPIO_Pin_4;
GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOA, &GPIO_InitStruct);
// connect SPI1 pins to SPI alternate function
//GPIO_PinAFConfig(GPIOA, GPIO_PinSource4, GPIO_AF_SPI1);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource5, GPIO_AF_SPI1);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource6, GPIO_AF_SPI1);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource7, GPIO_AF_SPI1);
//Set chip select high
GPIOA->BSRRL |= GPIO_Pin_4; // set PE4 high
// enable peripheral clock
RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);
/* configure SPI1 in Mode 0
* CPOL = 0 --> clock is low when idle
* CPHA = 0 --> data is sampled at the first edge
*/
SPI_StructInit(&SPI_InitStruct); // set default settings
SPI_InitStruct.SPI_Direction = SPI_Direction_2Lines_FullDuplex; // set to full duplex mode, seperate MOSI and MISO lines
SPI_InitStruct.SPI_Mode = SPI_Mode_Master; // transmit in master mode, NSS pin has to be always high
SPI_InitStruct.SPI_DataSize = SPI_DataSize_8b; // one packet of data is 8 bits wide
SPI_InitStruct.SPI_CPOL = SPI_CPOL_Low; // clock is low when idle
SPI_InitStruct.SPI_CPHA = SPI_CPHA_1Edge; // data sampled at first edge
SPI_InitStruct.SPI_NSS = SPI_NSS_Soft ; // set the NSS management to internal and pull internal NSS high
SPI_InitStruct.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_4; // SPI frequency is APB2 frequency / 4
SPI_InitStruct.SPI_FirstBit = SPI_FirstBit_MSB;// data is transmitted MSB first
SPI_Init(SPI1, &SPI_InitStruct);
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
NVIC_InitStructure.NVIC_IRQChannel = SPI1_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
/* Enable SPI1*/
SPI_Cmd(SPI1, ENABLE);
return;
}
Then i just loopback SPI_MOSI to SPI_MISO and use a function that transmit the data (a very basic function that takes data from a buffer and then uses CMSIS functions for the transmission). The problem is that when the SPI interrupt is triggered, the program won't get out from the handler. the handler function looks lihe this:
void SPI1_IRQHandler()
{
int a;
a++;
SPI_I2S_ClearITPendingBit(SPI1,SPI_I2S_IT_TXE);
return;
}
Is it a problem in the CMSIS library, or I am not configuring the SPI interrupt in the good way? Please guide me to the right point.
EDIT
This is the function i use for data transmission
void write_SPI1()
{
int i;
for (i=0;i<SPI_TX_MAX; i++)
{
SPI_I2S_SendData(SPI1,spiTxBuff[i]);
SPI_I2S_ITConfig(SPI1,SPI_I2S_IT_RXNE,ENABLE);
}
}
and the interruption deals with the data reception, it just fill spiRxBuff when receiving new data.
void SPI1_IRQHandler()
{
while (SPI_I2S_GetFlagStatus(SPI1,SPI_I2S_FLAG_RXNE)== RESET);
spiRxBuff[spiRxCount]= SPI_I2S_ReceiveData(SPI1);
spiRxCount++;
}
The variable used for Reception / Transmission are declared as below :
uint8_t spiTxBuff[SPI_TX_MAX] = {0x01,0x02,0x03,0x04,0x05,0x06};
uint8_t spiRxBuff[SPI_RX_MAX];
static volatile int spiRxCount= 0; // used in SPI1_IRQHandler
what is strange now is that i'am having {0x01,0x02,0x03,0x05,0x06} in spiRxBuff instead of {0x01,0x02,0x03,0x04,0x05,0x06}, but using debug mode the data in spiRxBuff are correct, what goes wrong in your opinion ?
You did not show the function doing the transmit, so I don't know exactly what are you trying to accomplish
Transmitting in a loop
If you are transmitting from a function (in a loop), then you don't need interrupts at all, just make sure that the TXE flag is set before you transmit. Note that you have to interleave sending and receiving somehow.
void SPI1_Transmit(uint8_t *send, uint8_t *receive, int count) {
while(count-- > 0) {
while(SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE)!=SET) {
if(SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE)==SET)
*receive++ = SPI_I2S_ReceiveData(SPI1);
}
SPI_I2S_SendData(SPI1, *send++);
}
while(SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE)!=SET) {
/* wait for the last incoming byte */
}
*receive++ = SPI_I2S_ReceiveData(SPI1);
}
Transmitting from interrupt
The TXE interrupt flag is set as long as the SPI device is not busy sending. If you don't do something about it in the interrupt handler, it will trigger an interrupt immediately again and again. You can't clear it manually, but by transmitting another byte, and resetting the transmit interrupt enable flag before sending the last byte.
volatile int spi1_tx_count, spi1_rx_count;
uint8_t *spi1_tx_ptr;
volatile uint8_t *spi1_rx_ptr;
/* set these global variables before enabling interrupts */
void SPI1_IRQHandler() {
if (SPI_I2S_GetITStatus(SPI1, SPI_I2S_IT_TXE) == SET) {
if(--spi1_tx_count < 1)
SPI_I2S_ITConfig(SPI1, SPI_I2S_IT_TXE, DISABLE);
SPI_I2S_SendData(SPI1, *spi1_tx_ptr++);
}
if(SPI_I2S_GetITStatus(SPI1, SPI_I2S_IT_RXNE) == SET) {
*spi_rx_ptr++ = SPI_I2S_ReceiveData(SPI1);
spi1_rx_count++;
}
}
Using DMA
The above examples are using processor power and cycles for a task that can be handled by the DMA conroller alone. A lot of (if not all) processor cycles, if you are talking to a peripheral at 2 MBit/s.
See Project/STM32F4xx_StdPeriph_Examples/SPI/SPI_TwoBoards in the library for an example.
Sorry, I haven't noticed at all that you've amended the question. Look like notifications are sent on new comments or answers, but not on edits.
There are multiple problems with your code. In write_SPI1(), I'd enable RX interrupt only once before the loop, there is no need to do it again and again. Also, you should definitely check whether the TX register is available before sending.
void write_SPI1() {
int i;
SPI_I2S_ITConfig(SPI1,SPI_I2S_IT_RXNE,ENABLE);
for (i=0;i<SPI_TX_MAX; i++) {
while(SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE)!=SET)
;
SPI_I2S_SendData(SPI1,spiTxBuff[i]);
}
}
It is however a bad idea to wait on a flag in the interrupt handler. If RXNE is the only possible interrupt source, then you can proceed straight to receiving.
I need to write a program to implement real time clock for ARM architecture. example: LPC213x
It should display Hour Minute and Seconds. I have no idea about ARM so having trouble getting started.
My code below is not working
// ...
int main (void) {
int hour=0;
int min=0;
int sec;
init_serial(); /* Init UART */
Initialize();
CCR=0x11;
PCONP=0x1815BE;
ILR=0x1; // Clearing Interrupt
//printf("\nTime is %02d:%02x:%02d",hour,min,sec);
while (1) { /* Loop forever */
}
}
void Initialize()
{
VPBDIV=0x0;
//CCR=0x2;
//ILR=0x3;
HOUR=0x0;
SEC=0x0;
MIN=0x0;
ILR = 0x03;
CCR = (1<<4) | (1<<0);
VICVectAddr13 = (unsigned)read_rtc;
VICVectCntl13 |= 0x20 | VIC_RTC;
VICIntEnable |= (1 << VIC_RTC);
}
/* Interrupt Service Routine*/
__irq void read_rtc()
{
int hour=0;
int min=0;
int sec;
ILR=0x1; // Clearing Interrupt
hour=(CTIME0 & MASKHR)>>16;
min= (CTIME0 & MASKMIN)>>8;
sec=CTIME0 & MASKSEC;
printf("\nTime is %02d:%02x:%02d",hour,min,sec);
//VICVectAddr=0xff;
VICVectAddr = 0;
}
According to this board description for the LPC213x, it is delivered with an example program called "Real-Time Clock - Demonstrates how the real-time clock can be used". This also implies that the board features real-time clock hardware, which is going to make it a lot easier.
I suggest you read up on that program, to figure out how to talk to the RTC hardware. The next step would be to solve the display requirements. The two obvious choices are either 7-segment LED displays, or an LCD.
Both are well-known technologies about which loads have been written, follow the Wikipedia links to find out more.
This is all for the LPC2468. We have a setTime function too, but I don't want to do ALL the work for you. ;) We have custom register files for ease of access, but if you look at the LPC manual, it's obvious where they correlate. You just have to shift values into the right place, and do bitwise operations. For example:
#define RTC_HOUR (*(volatile RTC_HOUR_t *)(RTC_BASE_ADDR + (uint32_t)0x28))
Time struture:
typedef struct {
uint8_t seconds; /* Second value - [0,59] */
uint8_t minutes; /* Minute value - [0,59] */
uint8_t hour; /* Hour value - [0,23] */
uint8_t mDay; /* Day of the month value - [1,31] */
uint8_t month; /* Month value - [1,12] */
uint16_t year; /* Year value - [0,4095] */
uint8_t wDay; /* Day of week value - [0,6] */
uint16_t yDay; /* Day of year value - [1,365] */
} rtcTime_t;
RTC functions:
void rtc_ClockStart(void) {
/* Enable CLOCK into RTC */
scb_ClockStart(M_RTC);
RTC_CCR.B.CLKSRC = 1;
RTC_CCR.B.CLKEN = 1;
return;
}
void rtc_ClockStop(void) {
RTC_CCR.B.CLKEN = 0;
/* Disable CLOCK into RTC */
scb_ClockStop(M_RTC);
return;
}
void rtc_GetTime(rtcTime_t *p_localTime) {
/* Set RTC timer value */
p_localTime->seconds = RTC_SEC.R;
p_localTime->minutes = RTC_MIN.R;
p_localTime->hour = RTC_HOUR.R;
p_localTime->mDay = RTC_DOM.R;
p_localTime->wDay = RTC_DOW.R;
p_localTime->yDay = RTC_DOY.R;
p_localTime->month = RTC_MONTH.R;
p_localTime->year = RTC_YEAR.R;
}
System control block functions:
void scb_ClockStart(module_t module) {
PCONP.R |= (uint32_t)1 << module;
}
void scb_ClockStop(module_t module) {
PCONP.R &= ~((uint32_t)1 << module);
}
If you need information about ARM then this ARM System Developer's Guide: Designing and Optimizing System Software may help you.
We used to do some thing like this for ARM.
#include "LPC21xx.h"
void rtc()
{
*IODIR1 = 0x00FF0000;
// Set LED ports to output
*IOSET1 = 0x00020000;
*PREINT = 0x000001C8;
// Set RTC prescaler for 12.000Mhz Xtal
*PREFRAC = 0x000061C0;
*CCR = 0x01;
*SEC = 0;
*MIN = 0;
*HOUR= 0;
}
A real-time clock (RTC) is a computer clock (most often in the form of an integrated circuit) that keeps track of the current time. Although the term often refers to the devices in personal computers, servers and embedded systems, RTCs are present in almost any electronic device which needs to keep accurate time.
You May refer this two link, i am sure it will give you further understanding :-
1). ARM Cortex Programming using CMSIS:- http://www.firmcodes.com/cmsis/
2). RTC Programming with ARM7:- http://www.firmcodes.com/microcontrollers/arm/real-time-clock-of-arm7-lpc2148/