I am trying to communicate with GSM module via UART communication. I could get message from the module as I expected. However when it comes to while loop (it is empty), debug session ends with "can not access target" error. Stepo by step, I am going to share my code:
Function 1 is AT_Send. (Note: Some of variables are declared globally.)
int AT_Send(UART_HandleTypeDef *huart, ATHandleTypedef *hat, unsigned char *sendBuffer, uint8_t ssize, unsigned char *responseBuffer, uint8_t rsize) {
if (HAL_UART_Transmit_IT(huart,sendBuffer,ssize) != HAL_OK) {
return -1;
}
while ((HAL_UART_GetState(huart) & HAL_UART_STATE_BUSY_TX) == HAL_UART_STATE_BUSY_TX) {
continue;
}
//;HAL_Delay(1000);
if (strstr((char*)receiveBuffer,(char*)responseBuffer) != NULL) {
rxIndex = 0;
memset(command, 0, sizeof(command));
return 0;
}
rxIndex = 0;
memset(command, 0, sizeof(command));
return 1;
}
Second function is AT_Init function. It sends AT to get OK response. At this point on, if I am not wrong, I am opening receive interrrupt and I am trying to get 1 byte.
int AT_Init(UART_HandleTypeDef *huart, ATHandleTypedef *hat)
{
HAL_UART_Receive_IT(huart,&rData,1);
tx = AT_Send(huart,hat,"AT\r",sizeof("AT\r\n"),"OK\r\n",sizeof("OK\r\n"));
return tx;
}
After these two functions, I am calling receive IT function in the call back while there are data on the bus.
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
if (huart->Instance == USART1){
command[rxIndex] = rData;
rxIndex++;
if((rxIndex == 2) && (strstr((char*)command,"\r\n") != NULL)) {
rxIndex = 0;
} else if (strstr((char*)command,"\r\n") != NULL) {
memcpy(receiveBuffer, command, sizeof(command));
rxIndex = 0;
memset(command,0,sizeof(command));
}
HAL_UART_Receive_IT(&huart1,&rData,1);
}
}
Moreover, I am going to send a few HTTP commands simultaneously if I can get rid of this problem.
Can anyone share his/her knowledge?
Edit: Main function is shown below
tx = AT_Init(&huart1,&hat);
while (1)
{
HAL_GPIO_TogglePin(GPIOB,GPIO_PIN_3);
HAL_Delay(500);
}
Edit 2: I had replaced uart channel by USART2, and debugger worked. I suppose that it is related to hardware. Still, I am curious about possible reasons that cause to this problem.
The question doesn't mention on which µC the program is running, I only see the "stm32" tag. Similarly, we don't know which debug protocol is used (JTAG or SWD?).
Still, I dare to guess that the toggle command for GPIO port PB3 in the main loop is causing the observations: On many (most? all?) STM32 controllers, PB3 is used as JTDO pin, which is needed for JTAG debug connections.
Please make sure to configure the debug connection to SWD (without SWO, i.e., neither SWV is correct). It may also help to check the wiring of the debug cable, the fast toggle at the PB3/JTDO line may influence the signal levels on some neighbouring SWD lines if the wiring is low quality or a fast SWD speed has been chosen.
My hypothesis can be falsified by removing all actions to PB3. If the problem remains, I'm wrong.
Related
The landscape - I have a MCU that performs a lot of tasks. It exposes an I2C slave communication to a Raspberry Pi. There a number of 'registers' I have created in code on the MCU. All of these are working fine. I previously had a nano hooked up and tested everything on the MCU so I am fairly sure the MCU is behaving correctly. Most of my I2C communications are working on the Pi too. Except for one. It is a little different in that it writes three bytes.
This is my code for the RPi:
std::string i2cServo(uint8_t reg, uint8_t angle){
std::string error;
uint8_t TxBuf[3];
TxBuf[0] = 11; // The register.
TxBuf[1] = reg; // The first parameter.
TxBuf[2] = angle; // The second parameter.
close_fd();
if (!fd) {
if (open_fd_wronly() == -1) {
error = "Failed to open I2C bus.";
} else {
if (write(fd, &TxBuf, 3) != 3) {
std::cerr << errno << std::endl;
error = "Could not set servo.";
}
}
}
return error;
}
This code gets executed twice. The first time everything is fine, the second I get errno 5. Which is EIO.
This is the logic analyser output:
You can see the first pass is fine. The second pass is also fine till the end when a stop is expected.
I would suspect the MCU if it wasn't for the fact the nano behaves correctly, and the first pass of the code works fine.
Any ideas?
This is the fd opening:
int open_fd_wronly(){
error_flag = false;
if (fd) {
close_fd();
fd = 0;
}
if ((fd = open(devicefile.c_str(), O_WRONLY)) < 0)
return errorMsg("ERROR opening: " + devicefile + "\n");
if (ioctl(fd, I2C_SLAVE, slave_address) < 0)
return errorMsg("ERROR address: " + std::to_string(slave_address) + "\n");
return 0;
}
Sorry, no sooner posted the question. Than the answer dawned on me. It really helps to share a problem. The first register call prompts a write to EEPROM the second call was just arriving too fast triggering another write to the EEPROM and causing a crash. A little delay between the two calls solved the problem.
Many thanks.
I'm gonna to read/write under the modbus-tcp specification.
So, I'm trying to code the client and server in the linux environment.
(I would communicate with the windows program(as a client) using the modbus-tcp.)
but it doesn't work as I want, so I ask you here.
I'm testing the client code for linux as a client and the easymodbus as a server.
I used the libmodbus code.
I'd like to read coil(0x01) and write coil(0x05).
When the code is executed using the libmodbus, 'ff' is printed out from the Unit ID part.(according to the manual, 01 should be output for modbus-tcp.
I don't know why 'ff' is printed(photo attached).
Wrong result:
Expected result:
'[00] [00] .... [00]' ; Do you know where to control this part?
Do you have or do you know the sample code that implements the 'read/write' function using the libmodbus?
please let me know the information, if you know that.
ctx = modbus_new_tcp("192.168.0.99", 502);
modbus_set_debug(ctx, TRUE);
if (modbus_connect(ctx) == -1) {
fprintf(stderr, "Connection failed: %s\n",
modbus_strerror(errno));
modbus_free(ctx);
return -1;
}
tab_rq_bits = (uint8_t *) malloc(nb * sizeof(uint8_t));
memset(tab_rq_bits, 0, nb * sizeof(uint8_t));
tab_rp_bits = (uint8_t *) malloc(nb * sizeof(uint8_t));
memset(tab_rp_bits, 0, nb * sizeof(uint8_t));
nb_loop = nb_fail = 0;
/* WRITE BIT */
rc = modbus_write_bit(ctx, addr, tab_rq_bits[0]);
if (rc != 1) {
printf("ERROR modbus_write_bit (%d)\n", rc);
printf("Address = %d, value = %d\n", addr, tab_rq_bits[0]);
nb_fail++;
} else {
rc = modbus_read_bits(ctx, addr, 1, tab_rp_bits);
if (rc != 1 || tab_rq_bits[0] != tab_rp_bits[0]) {
printf("ERROR modbus_read_bits single (%d)\n", rc);
printf("address = %d\n", addr);
nb_fail++;
}
}
printf("Test: ");
if (nb_fail)
printf("%d FAILS\n", nb_fail);
else
printf("SUCCESS\n");
free(tab_rq_bits);
free(tab_rp_bits);
/* Close the connection */
modbus_close(ctx);
modbus_free(ctx);
return 0;
That FF you see right before the Modbus function is actually correct. Quoting the Modbus Implementation Guide, page 23:
On TCP/IP, the MODBUS server is addressed using its IP address; therefore, the
MODBUS Unit Identifier is useless. The value 0xFF has to be used.
So libmodbus is just sticking to the Modbus specification. I'm assuming, then, that the problem is in easymodbus, which is apparently expecting you to use 0x01as the unit id in your queries.
I imagine you don't want to mess with easymodbus, so you can fix this problem pretty easily from libmodbus: just change the default unit id:
modbus_set_slave(ctx, 1);
You could also go with:
rc = modbus_set_slave(ctx, MODBUS_BROADCAST_ADDRESS);
ASSERT_TRUE(rc != -1, "Invalid broadcast address");
to make your client address all slaves within the network, if you have more than one.
You have more info and a short explanation of where this problem is coming from in the libmodbus man page for modbus_set_slave function.
For a very comprehensive example, you can check libmodbus unit tests
And regarding your question number 5, I don't know how to answer it, the zeros you mean are supposed to be the states (true or false) you want to write (or read) to the coils. For writing you can change them with the value field of function modbus_write_bit(ctx, address, value).
I'm very grateful for your reply.
I tested the read/write function using the 'unit-test-server/client' code you recommended.
I've reviewed the code, but there are still many things I don't know.
However, there is an address value that acts after testing each other with unit-test-server/client code and there is an address value that does not work
(Do you know why?).
-Checked and found that the UT_BITS_ADDRESS (address value) value operates from 0x130 to 0x150
-'error Illegal data address' occurs at values below -0x130 and above 0x150
-The address I want to read/write is 0x0001 to 0x0004(Do you know how to do?).
I want to know how to process and transmit data like the TX part of the right picture.
enter image description here
I'm running both client and server in my Linux environment and I'm doing read/write testing.
Among the wrong pictures...[06][FF]... <-- I want to know how to modify FF part (to change the value to 01 as shown in the picture)
enter image description here
and "modbus_set_slave" is the function for modbus rtu?
I'd like to communicate PC Program and Linux device in the end.
so Which part do I use that function?
I thanks for your concern again.
Our products are using a well known CANopen stack, which uses socketCAN, on an embedded Beaglebone Black based system running under Ubuntu 14.04 LTS. But for some reason, even though the stack we're using will detect when the CAN bus goes into a PASSIVE state or even a BUS OFF state, it never indicates when the CAN bus recovers from errors and goes out of a PASSIVE or warning state, and enters a non error state.
If I were to query the socketCAN driver directly (via ioctl calls), would I be able to detect when the CAN bus goes in and out of a warning state (which is less than 127 errors), in and out of a PASSIVE state (greater than 127 errors) or goes BUS OFF (greater than 255 errors)?
I'd like to know if I'd be wasting my time doing this or is there a better way to detect, accurately and in real-time, all conditions of a CAN bus?
I have only a partial solution to that problem.
As you are using socketCAN, the interface is seen as a standard network interface, on which we can query the status.
Based on How to check Ethernet in Linux? (replace "eth0" by "can0"), you can check the link status.
This is not real-time, but can be executed in a periodic thread to check the bus state.
So while this is an old question, I just happened to stumble upon it (while searching for something only mildly related).
SocketCAN provides all the means for detecting error frames OOB.
Assuming your code looks similar to this:
int readFromCan(int socketFd, unsigned char* data, unsigned int* rxId) {
int32_t bytesRead = -1;
struct can_frame canFrame = {0};
bytesRead = (int32_t)read(socketFd, &canFrame, sizeof(can_frame));
if (bytesRead >= 0) {
bytesRead = canFrame.can_dlc;
if (data) {
memcpy(data, canFrame.data, readBytes);
}
if (rxId) {
*rxId = canFrame.can_id; // This will come in handy
}
}
return bytesRead;
}
void doStuffWithMessage() {
int32_t mySocketFd = fooGetSocketFd();
int32_t receiveId = 0;
unsigned char myData[8] = {0};
int32_t dataLength = 0;
if ((dataLength = readFromCan(mySocketFd, myData, &receiveId) == -1) {
// Handle error
return;
}
if (receiveId & CAN_ERR_MASK != 0) {
// Handle error frame
return;
}
// Do stuff with your data
}
I have stm32f4-discovery kit and I want to try i/o expander for hd44870 LCD . I have PCF8574AT link to io example like mine 8-bit expander where i2c address is 0x3f (checked by i2c scanner) on hi2c3 hardware. For c/c++ use HAL libraries on Eclipse environment. Ok take look at code.
First I initialize i2c3 - like Datasheet 100kHz on SCL:
static void MX_I2C3_Init(void)
{
hi2c3.Instance = I2C3;
hi2c3.Init.ClockSpeed = 100000;
hi2c3.Init.DutyCycle = I2C_DUTYCYCLE_2;
hi2c3.Init.OwnAddress1 = 0;
hi2c3.Init.AddressingMode = I2C_ADDRESSINGMODE_7BIT;
hi2c3.Init.DualAddressMode = I2C_DUALADDRESS_DISABLE;
hi2c3.Init.OwnAddress2 = 0;
hi2c3.Init.GeneralCallMode = I2C_GENERALCALL_DISABLE;
hi2c3.Init.NoStretchMode = I2C_NOSTRETCH_DISABLE;
if (HAL_I2C_Init(&hi2c3) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
}
Then try to send data to I/O expander. But before that I check that i/o is ready to use:
result = HAL_I2C_IsDeviceReady(&hi2c3,0x3f , 2, 2);
if (result == HAL_BUSY)
{
HD44780_Puts(6, 1, "busy");
}else{
HD44780_Puts(6, 1, "ready");
uint8_t data_io = 0xff;
HAL_I2C_Master_Transmit(&hi2c3, 0x3f, data_io, 1, 100);
}
On a same expander nothing changes. Any ideas what is wrong or maybe i/0 expander is broken ?
Im not sure about HAL driver, really never used HAL. But I have touched pcf8574 IO expander. As you said, you have checked it with scanner and if you get address, line and device is OK. As I am not expert on I2C and HAL libs,I'll show my I2C driver it relies on STM32 standard periphery drivers and it worked for PCF8574 and various I2C devices. There is an example,snippet(blocking mode, not irq based):
Checking if IO is not busy.
while(I2C_GetFlagStatus(&I2Cx, I2C_FLAG_BUSY) == SET){
if((timeout--) == 0) return -ETIMEDOUT;
}
Generate start condition and set write condition(with address for write mode).
I2C_TransferHandling(&I2Cx, dev_addr, 1, I2C_SoftEnd_Mode, I2C_Generate_Start_Write);
while(I2C_GetFlagStatus(&I2Cx, I2C_ISR_TXIS) == RESET){
if((timeout--) == 0) return -ENODEV;
}
Now you can send data byte( it is your IO states), This function writes directly to I2C TX(transceiver) register :
I2C_SendData(&I2Cx, reg_addr);
while(I2C_GetFlagStatus(&I2Cx, I2C_ISR_TC) == RESET){
if((timeout--) == 0) return -EIO;
}
Generate reading condition and than read from PCF8574, data should be same as it was just written(if nothing toggles IO expander). Basically you can read byte or more bytes (depends on device). In your case PCF8574(8bit) gives only 1 byte.
I2C_TransferHandling(dev->channel,dev_addr, len, I2C_AutoEnd_Mode,I2C_Generate_Start_Read);
size_t i;
for(i=0;i<len;i++){
timeout = I2C_TIMEOUT;
while(I2C_GetFlagStatus(dev->channel, I2C_ISR_RXNE) == RESET){
if((timeout--) == 0) return -EIO;
}
data[i] = I2C_ReceiveData(dev->channel);
}
You can continue RW operations, or just simply wait till device automatically stop transition on line:
while(I2C_GetFlagStatus(&I2Cx, I2C_FLAG_STOPF) == RESET){
if((timeout--) == 0) return -EIO;
}
I2C_ClearFlag(&I2Cx, I2C_ICR_STOPCF);
This steps will write and read data. Anyway this chip has some tricky logic there, it more simplistic than it looks like.Actually it works just as simple OUTPUT. Extern input just triggers up PCF8574 pin and nothing more, no special configuration for input mode. For input monitor for sure use PCF8574 INT pin, PCF8574 will trigger INT pin.
For example:
If you want input pins, than just simply set pins to logic zero. And monitor INT pin,if change happens on input, INT pin will be triggered and you should read data via I2C .
For OUTPUT low just write zero's.
And for OUTPUT high set logic true.
You are using HAL so you have to read what happens inside HAL_I2C_Master_Transmit function. Do not forget that address is 7bit and first byte with address also includes R/W condition.First byte bit0 is R/W bit. So you should handle it.
for example with defines:
#define PCF8574_WRITE_ADRESS (0x40) /*for writing to chip*/
#define PCF8574_READ_ADRESS ((0x40)|0x01) /*for reading chip*/
Here is some links:
i2c explanations
this may help
Really nice guide!
Hope this will help to understand your problem and solve it.:)
thanks , Bulkin
I found obvious mistake . HAL libs do not i2c_address << 1 . I/YOU must put that in code not same result !
HAL_I2C_Master_Transmit(&hi2c3, (0x3f<<1), data_io, 1, 100);
or
$define i2c_address_write (0x3f <<1 )
HAL_I2C_Master_Transmit(&hi2c3, i2c_address_write , data_io, 1, 100);
to read :
$define i2c_address_read ((0x3f <<1) | 0x01)
HAL_I2C_Master_Transmit(&hi2c3, i2c_address_read , data_io, 1, 100);
I've been porting newlib to my very small kernel, and I'm stumped: whenever I include a function that references a system call, my program will page fault on execution. If I call a function that does not reference a system call, like rand(), nothing will go wrong.
Note: By include, I mean as long as the function, e.g. printf() or fopen(), is somewhere inside the program, even if it isn't called through main().
I've had this problem for quite some time now, and have no idea what could be causing this:
I've rebuilt newlib numerous times
Modified my ELF loader to load the
code from the section headers instead of program headers
Attempted to build newlib/libgloss separately (which failed)
Linked the libraries (libc, libnosys) through the ld script using GROUP, gcc and ld
I'm not quite sure what other information I should include with this, but I'd be happy to include what I can.
Edit: To verify, the page faults occurring are not at the addresses of the failing functions; they are elsewhere in the program. For example, when I call fopen(), located at 0x08048170, I will page fault at 0xA00A316C.
Edit 2:
Relevant code for loading ELF:
int krun(u8int *name) {
int fd = kopen(name);
Elf32_Ehdr *ehdr = kmalloc(sizeof(Elf32_Ehdr*));
read(fd, ehdr, sizeof(Elf32_Ehdr));
if (ehdr->e_ident[0] != 0x7F || ehdr->e_ident[1] != 'E' || ehdr->e_ident[2] != 'L' || ehdr->e_ident[3] != 'F') {
kfree(ehdr);
return -1;
}
int pheaders = ehdr->e_phnum;
int phoff = ehdr->e_phoff;
int phsize = ehdr->e_phentsize;
int sheaders = ehdr->e_shnum;
int shoff = ehdr->e_shoff;
int shsize = ehdr->e_shentsize;
for (int i = 0; i < pheaders; i++) {
lseek(fd, phoff + phsize * i, SEEK_SET);
Elf32_Phdr *phdr = kmalloc(sizeof(Elf32_Phdr*));
read(fd, phdr, sizeof(Elf32_Phdr));
u32int page = PMMAllocPage();
int flags = 0;
if (phdr->p_flags & PF_R) flags |= PAGE_PRESENT;
if (phdr->p_flags & PF_W) flags |= PAGE_WRITE;
int pages = (phdr->p_memsz / 0x1000) + 1;
while (pages >= 0) {
u32int mapaddr = (phdr->p_vaddr + (pages * 0x1000)) & 0xFFFFF000;
map(mapaddr, page, flags | PAGE_USER);
pages--;
}
lseek(fd, phdr->p_offset, SEEK_SET);
read(fd, (void *)phdr->p_vaddr, phdr->p_filesz);
kfree(phdr);
}
// Removed: code block that zeroes .bss: it's already zeroed whenever I check it anyways
// Removed: code block that creates thread and adds it to scheduler
kfree(ehdr);
return 0;
}
Edit 3: I've noticed that if I call a system call, such as write(), and then call printf() two or more times, I will get an unknown opcode interrupt. Odd.
Whoops! Figured it out: when I map the virtual address, I should allocate a new page each time, like so:
map(mapaddr, PMMAllocPage(), flags | PAGE_USER);
Now it works fine.
For those curious as to why it didn't work: when I wasn't including printf(), the size of the program was under 0x1000 bytes, so mapping with only one page was okay. When I include printf() or fopen(), the size of the program was much bigger so that's what caused the issue.