Extra bytes sent when communicating at 115200 baud over USB serial (WinAPI) - c

I'm attempting to send serial messages over USB to an Arduino Uno, using raw WinAPI commands. When using baud rates less than 115200, it works perfectly fine. However, when I send at 115200 baud, two extra bytes are sent prefixing the data I sent, but ONLY for the first message after connecting to the Arduino. For example, if I connect to the Arduino and send two bytes, "Hi", the Arduino receives "ððHi". If I send "Hi" again, the Arduino receives "Hi" like it should. (The extra bytes are usually ð (0xF0), but not always.)
I know that my computer and the Arduino are capable of communicating at 115200 baud, because other programs such as avrdude and the Arduino IDE's serial monitor can do it fine.
I have tried clearing the RX and TX buffers on both sides and also messing the DCB settings, with no effect. Does anyone know what might be causing this?
Thanks!
Here is my code to reproduce the problem:
Computer side:
#include <Windows.h>
int main()
{
// Open device as non-overlapped
HANDLE device = CreateFile(L"COM6",
GENERIC_READ | GENERIC_WRITE,
0,
NULL,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL,
NULL);
// Make sure the device is valid
if(device == INVALID_HANDLE_VALUE)
return 0;
DCB dcb;
if(!GetCommState(device, &dcb))
return 0;
dcb.fOutX = 0;
dcb.fInX = 0;
dcb.fDtrControl = DTR_CONTROL_DISABLE;
dcb.fRtsControl = RTS_CONTROL_DISABLE;
dcb.fNull = 0;
dcb.BaudRate = CBR_115200;
dcb.ByteSize = 8;
dcb.Parity = NOPARITY;
dcb.StopBits = ONESTOPBIT;
if(!SetCommState(device, &dcb))
return 0;
COMMTIMEOUTS Timeouts = { 0 };
Timeouts.ReadTotalTimeoutConstant = 1000;
Timeouts.WriteTotalTimeoutConstant = 1000;
if(!SetCommTimeouts(device, &Timeouts))
return 0;
char *buf = "abcdef";
DWORD written;
WriteFile(device, buf, 6, &written, NULL);
DWORD read;
char inbuf[100];
ReadFile(device, inbuf, 100, &read, NULL);
// When I get the result inbuf, it has 8 bytes: {0xF0, 0xF0, a, b, c, d, e, f}
// Doing a 2nd set of Write/ReadFile, with the same message, gives the correct response
return 0;
}
Arduino side:
void setup()
{
Serial.begin(115200);
}
void loop()
{
if(Serial.available())
Serial.write(Serial.read());
}

Related

Sampling analog signals on the ESP32 at different rates using I2S

I need to read high freq. analog signal data from one ADC1 channel and read low freq. data from other ADC1 pins.
I use I2S for the high freq. data read, which runs perfectly, but as soon as I2S is configured all other ADC1 pins read 4095 only.
What is the correct handling for my demands?
Can't use ADC2 because of wifi.
Code excerpt:
void readerTask(void *param) {
size_t bytesRead = 0;
while(true) {
// Get ADC data from DMA buffer
i2s_read(I2S_NUM_0, buf, sizeof(buf), &bytesRead, portMAX_DELAY);
// prevent the data getting corrupted
i2s_adc_disable(I2S_NUM_0);
/* data processing */
delay(30);
i2s_adc_enable(I2S_NUM_0);
}
}
void setup() {
i2s_config_t i2s_config = {
.mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_RX | I2S_MODE_ADC_BUILT_IN),
.sample_rate = 8000,
.bits_per_sample = I2S_BITS_PER_SAMPLE_16BIT,
.channel_format = I2S_CHANNEL_FMT_ONLY_LEFT,
.communication_format = I2S_COMM_FORMAT_I2S_LSB,
.intr_alloc_flags = ESP_INTR_FLAG_LEVEL1,
.dma_buf_count = 2,
.dma_buf_len = 1024,
.use_apll = false,
.tx_desc_auto_clear = false,
.fixed_mclk = 0};
//install and start i2s driver
i2s_driver_install(I2S_NUM_0, &i2s_config, 0, NULL);
//init ADC pad
i2s_set_adc_mode(ADC_UNIT_1, ADC1_CHANNEL_0);
// enable the ADC
i2s_adc_enable(I2S_NUM_0);
// start a task to read samples from I2S
xTaskCreatePinnedToCore(readerTask, "Reader Task", 2048, NULL, 1, NULL, 0);
}
void loop()
{
EVERY_N_MILLISECONDS( 100 ) {
// read low freq. data
int test = analogRead(34); // will always read 4095
}
}
you need:
i2s_adc_disable(I2S_NUM_0);
i2s_driver_uninstall(I2S_NUM_0);
analogRead(34);
i2s_driver_install(I2S_NUM_0, &i2s_config, 0, NULL);
i2s_set_adc_mode(ADC_UNIT_1, ADC1_CHANNEL_0);
i2s_adc_enable(I2S_NUM_0);

Receive Inconsistency in the dspic33f controller using Interrupts

I m using dspic33f series micro controller to receive SMS from modem SIM800A. I m using interrupt method to receive response from the modem using serial communication . If I send more than one AT command to modem via UART sequentially I'm getting response into the recieve buffer only for 1st command and no response in the receive buffer for the remaining commands though the modem was responding.
After debugging I found the reason for this peculiar behavior. The reason was I was clearing the receive buffer after receiving the response into the buffer and printing on the console i.e. before sending next command to modem via UART using memset function in c.
But on commenting this memset function i was able receive the response into the receive buffer for the all the AT commands that was sent sequentially, if the memset function is not commented then no response is filled in the receive buffer though the modem was responding so please help out in receiving the response into the buffer.
Code which i have written
#include "p33FJ64GS606.h"
#include <stdio.h>
#define FCY 40000000UL
#include <libpic30.h>
#include <string.h>
_FOSC(FCKSM_CSECMD & OSCIOFNC_OFF)
_FWDT(FWDTEN_OFF)
_FPOR(FPWRT_PWR128 )
_FICD(ICS_PGD1 & JTAGEN_OFF)
char StringLoop[161];
void Init_Uart1(int uart_no)
{
U1MODEbits.STSEL = 0; // 1-Stop bit
U1MODEbits.PDSEL = 0; // No Parity, 8-Data bits
U1MODEbits.ABAUD = 0; // Auto-Baud disabled
U1MODEbits.BRGH = 0; // Standard-Speed mode
U1BRG = UBRG1_VALUE; // Baud Rate setting for 115200
U1STAbits.UTXISEL0 = 0; // Interrupt after one TX character is transmitted
U1STAbits.UTXISEL1 = 0;
U1STAbits.URXISEL0 = 0;
U1STAbits.URXISEL1 = 0;//jkv
IEC0bits.U1RXIE = 1;
IEC0bits.U1TXIE = 0; // Enable UART TX interrupt
U1MODEbits.UARTEN = 1; // Enable UART
U1STAbits.UTXEN = 1; // Enable UART TX
U1MODEbits.USIDL=0;
}
void UART1_puts(unsigned char data)
{
while (U1STAbits.TRMT==0);
U1TXREG = data;
}
void UART1_send(unsigned char *s)
{
memset(StringLoop,'\0',sizeof(StringLoop)); /* if I comment this line then i can receive the response into the buffer StringLoop continuously else i receive the response only for the 1st AT command and I don't get the response for other AT commands into the StringLoop though the modem is responding*/
while(*s)
{
UART1_puts(*s);
s++;
}
}
void __attribute__((interrupt, no_auto_psv)) _U1RXInterrupt(void)
{
if(IFS0bits.U1RXIF)
{
StringLoop[rcindex++] = U1RXREG;
if (rcindex >= (sizeof(StringLoop) - 1))
rcindex = 0;
}
IFS0bits.U1RXIF=0;
}
}
void main()
{
int i=0,j=0;
Init_Clocks();
Init_Uart2(1);
Init_Uart1(1);
TRISFbits.TRISF1=0;
LATFbits.LATF1=1;
UART1_send("AT+CMGR=1\r\n");
__delay_ms(2000);
printf("stringloop is %s\n",StringLoop);
UART1_send("AT+CPMS=?\r\n");
__delay_ms(2000);
printf("stringloop is %s\n",StringLoop);
UART1_send("AT+CPMS?\r\n");
__delay_ms(2000);
printf("stringloop is %s\n",StringLoop);
}

Serial communication between linux and 8051 microcontroller board using rs-232 in c

I have problem in sending data serially using RS-232 from linux OS to uc 8051.
8051 setting:
baudrate = 9600;
comport = port1.
parity = none
stop bit = one
// my code for receiving data on 8051 uc
#include <reg51.h>
unsigned char value;
int i,j;
void ini()
{
TMOD=0x20; //Timer1, mode 2, baud rate 9600 bps
TH1=0XFD;
SCON=0x50;
TR1=1;
}
void delay()
{
for(i=0;i<=1000;i++)
for (j=0;j<=300;j++);
}
void recieve()
{
unsigned char value;
while(RI==0);
value=SBUF;
P1=value;
RI=0;
}
void main()
{
while(1)
{
ini();
recieve();
}
}
// and code which run on linux is as following
#include <stdio.h> // standard input / output functions
#include <string.h> // string function definitions
#include <unistd.h> // UNIX standard function definitions
#include <fcntl.h> // File control definitions
#include <errno.h> // Error number definitions
#include <termios.h> // POSIX terminal control definitionss
#include <time.h> // time calls
int open_port(void)
{
int fd; // file description for the serial port
fd = open("/dev/ttyS0", O_RDWR | O_NOCTTY | O_NDELAY);
if (fd == -1) // if open is unsucessful
{
//perror("open_port: Unable to open /dev/ttyS0 - ");
printf("open_port: Unable to open /dev/ttyS0. \n");
}
else
{
fcntl(fd, F_SETFL, 0);
printf("port is open.\n");
}
return(fd);
} //open_port
int configure_port(int fd) // configure the port
{
struct termios port_settings; // structure to store the port settings in
cfsetispeed(&port_settings, B9600); // set baud rates
cfsetospeed(&port_settings, B9600);
port_settings.c_cflag &= ~PARENB; // set no parity, stop bits, data bits
port_settings.c_cflag &= ~CSTOPB;
port_settings.c_cflag &= ~CSIZE;
port_settings.c_cflag |= CS8;
tcsetattr(fd, TCSANOW, &port_settings); // apply the settings to the port
return(fd);
} //configure_port
int query_modem(int fd) // query modem with an AT command
{
char n;
fd_set rdfs;
struct timeval timeout;
// initialise the timeout structure
timeout.tv_sec = 10; // ten second timeout
timeout.tv_usec = 0;
// Create byte array
unsigned char send_bytes[] = { 0x00, 0xff};
write(fd, send_bytes, 2); //Send data
printf("Wrote the bytes. \n");
// do the select
n = select(fd + 1, &rdfs, NULL, NULL, &timeout);
// check if an error has occured
if(n < 0)
{
perror("select failed\n");
}
else if (n == 0)
{
puts("Timeout!");
}
else
{
printf("\nBytes detected on the port!\n");
}
return 0;
} //query_modem
int main(void)
{
int fd = open_port();
configure_port(fd);
query_modem(fd);
return(0);
} // main
But I have problem .. so plz help me out and tell me in which format linux sends data through rs-232. Also receiving format of 8051 micro-controller.
Need sample code in C.
I recomment basic fault finding
make sure you use correct cables (2 & 3 crossed out, no handshake lines to start with)
seperate the devices, i.e. connect your Linux machine to a PC running a terminal
program and try to establish 2-way communication - work on the Linux / C code until you achieve
connect your 8051 to a PC running a terminal program ....
connect Linux and 8051 only if they both work against a known and proven device
If your 8051 code sample represents all code .... how would the 8051 respond to the AT .... it can only receive.
good luck

baudrate serial windows port

To probe the windows serial port I have written this program. I set the serial port baudrate to 115200 bps. When I run this program the elapsed time is 1250 ms, so that, the baudrate only reachs 102400 bps. I also check in reception the baudrate with a similar program and the baudrate is the same.
Here is the program:
char* message =
"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
int numBytes = 144;
c0 = clock()
for (;;)
{
sendSerial(&hCom, message, numBytes );
tx +=numBytes;
//14400 bytes * 8 = 115200 bps
if (tx >= 14400)
{
c1 = clock();
runtime_diff_ms = (c1 - c0) * 1000. / CLOCKS_PER_SEC;
printf("Tx frames %d Time ms %f", tx, runtime_diff_ms);
system ("pause");
return -1;
}
}
bool sendSerial(HANDLE *hCom, char *WriteBuffer, DWORD dwBytesToWrite)
{
DWORD dwBytesWritten = 0;
BOOL bErrorFlag = FALSE;
bErrorFlag = WriteFile(
*hCom, // open file handle
WriteBuffer, // start of data to write
dwBytesToWrite, // number of bytes to write
&dwBytesWritten, // number of bytes that were written
NULL);
...
}
These are my serial port specifications:
DCB dcbSerialParams;
COMMTIMEOUTS timeouts;
dcbSerialParams.BaudRate=CBR_115200;
dcbSerialParams.ByteSize=8;
dcbSerialParams.StopBits=ONESTOPBIT;
dcbSerialParams.Parity=NOPARITY;
timeouts.ReadIntervalTimeout=MAXDWORD;
timeouts.ReadTotalTimeoutMultiplier=MAXDWORD;
timeouts.ReadTotalTimeoutConstant=5000; // 5sec
timeouts.WriteTotalTimeoutMultiplier=10;
timeouts.WriteTotalTimeoutConstant=100;
Anyone know how to fix this problem to reach 115200 bps?
There are 10 bits per character - 8 bits for the data plus a start and stop bit.
If you calculate how long 14400 characters at 10 bits per character should take at 115200 bps then you get 1250 ms:
(14400 characters * 10 bits/character) / (115200 bits/second) = 1.250 seconds

How to detect if a Bluetooth HID device was disconnected?

I'm using CreateFile to open an asynchronous file handle to a Bluetooth HID device on the system. The device will then start streaming data, and I use ReadFile to read data from the device. The problem is, that if the Bluetooth connection is dropped, ReadFile just keeps giving ERROR_IO_PENDING instead of reporting a failure.
I cannot rely on timeouts, because the device doesn't send any data if there is nothing to report. I do not want it to time out if the connection is still alive, but there is simply no data for a while.
Still, the Bluetooth manager (both the Windows one and the Toshiba one) do immediately notice that the connection was lost. So this information is somewhere inside the system; it's just not getting through to ReadFile.
I have available:
the file handle (HANDLE value) to the device,
the path that was used to open that handle (but I don't want to attempt to open it another time, creating a new connection...)
an OVERLAPPED struct used for asynchronous ReadFile.
I am not sure if this issue is Bluetooth-specific, HID-specific, or occurs with devices in general. Is there any way that I can either
get ReadFile to return an error when the connection was dropped, or
detect quickly upon a timeout from ReadFile whether the connection is still alive (it needs to be fast because ReadFile is called at least 100 times per second), or
solve this problem in another way I haven't thought of?
You are going to have to have some sort of polling to check. Unless there is a event you can attach (I'm not familiar with the driver), the simplest way is to poll your COM port by doing a ReadFile and check is dwBytesRead > 0 when you send a command. There should be some status command you can send or you can check if you can write to the port and copy those bytes written to dwBytesWrite using WriteFile, for instance, and check if that is equal to the length of bytes you are sending. For instance:
WriteFile(bcPort, cmd, len, &dwBytesWrite, NULL);
if (len == dwBytesWrite) {
// Good! Return true
} else
// Bad! Return false
}
This is how I do it in my application. Below may seem like a bunch of boilerplate code, but I think it will help you get to the root of your problem. I first open the Comm Port in the beginning.
I have an array of COM ports that I maintain and check to see if they are open before writing to a particular COM port. For instance, they are opened in the beginning.
int j;
DWORD dwBytesRead;
if (systemDetect == SYS_DEMO)
return;
if (port <= 0 || port >= MAX_PORT)
return;
if (hComm[port]) {
ShowPortMessage(true, 20, port, "Serial port already open:");
return;
}
wsprintf(buff, "COM%d", port);
hComm[port] = CreateFile(buff,
GENERIC_READ | GENERIC_WRITE,
0, //Set of bit flags that specifies how the object can be shared
0, //Security Attributes
OPEN_EXISTING,
0, //Specifies the file attributes and flags for the file
0); //access to a template file
if (hComm[port] != INVALID_HANDLE_VALUE) {
if (GetCommState(hComm[port], &dcbCommPort)) {
if(baudrate == 9600) {
dcbCommPort.BaudRate = CBR_9600;//current baud rate
} else {
if(baudrate == 115200) {
dcbCommPort.BaudRate = CBR_115200;
}
}
dcbCommPort.fBinary = 1; //binary mode, no EOF check
dcbCommPort.fParity = 0; //enable parity checking
dcbCommPort.fOutxCtsFlow = 0; //CTS output flow control
dcbCommPort.fOutxDsrFlow = 0; //DSR output flow control
// dcbCommPort.fDtrControl = 1; //DTR flow control type
dcbCommPort.fDtrControl = 0; //DTR flow control type
dcbCommPort.fDsrSensitivity = 0;//DSR sensitivity
dcbCommPort.fTXContinueOnXoff = 0; //XOFF continues Tx
dcbCommPort.fOutX = 0; //XON/XOFF out flow control
dcbCommPort.fInX = 0; //XON/XOFF in flow control
dcbCommPort.fErrorChar = 0; //enable error replacement
dcbCommPort.fNull = 0; //enable null stripping
//dcbCommPort.fRtsControl = 1; //RTS flow control
dcbCommPort.fRtsControl = 0; //RTS flow control
dcbCommPort.fAbortOnError = 0; //abort reads/writes on error
dcbCommPort.fDummy2 = 0; //reserved
dcbCommPort.XonLim = 2048; //transmit XON threshold
dcbCommPort.XoffLim = 512; //transmit XOFF threshold
dcbCommPort.ByteSize = 8; //number of bits/byte, 4-8
dcbCommPort.Parity = 0; //0-4=no,odd,even,mark,space
dcbCommPort.StopBits = 0; //0,1,2 = 1, 1.5, 2
dcbCommPort.XonChar = 0x11; //Tx and Rx XON character
dcbCommPort.XoffChar = 0x13; //Tx and Rx XOFF character
dcbCommPort.ErrorChar = 0; //error replacement character
dcbCommPort.EofChar = 0; //end of input character
dcbCommPort.EvtChar = 0; //received event character
if (!SetCommState(hComm[port], &dcbCommPort)) {
setBit(SystemState, SYSTEM_PORT_ERROR);
//ShowPortMessage(true, 21, port, "Cannot set serial port state information:");
if (!CloseHandle(hComm[port])) {
//ShowPortMessage(true, 22, port, "Cannot close serial port:");
}
hComm[port] = NULL;
return;
}
} else {
setBit(SystemState, SYSTEM_PORT_ERROR);
//ShowPortMessage(true, 29, port, "Cannot get serial port state information:");
if (!CloseHandle(hComm[port])) {
//ShowPortMessage(true, 22, port, "Cannot close serial port:");
}
hComm[port] = NULL;
return;
}
if (!SetupComm(hComm[port], 1024*4, 1024*2)) {
setBit(SystemState, SYSTEM_PORT_ERROR);
//ShowPortMessage(true, 23, port, "Cannot set serial port I/O buffer size:");
if (!CloseHandle(hComm[port])) {
//ShowPortMessage(true, 22, port, "Cannot close serial port:");
}
hComm[port] = NULL;
return;
}
if (GetCommTimeouts(hComm[port], &ctmoOld)) {
memmove(&ctmoNew, &ctmoOld, sizeof(ctmoNew));
//default setting
ctmoNew.ReadTotalTimeoutConstant = 100;
ctmoNew.ReadTotalTimeoutMultiplier = 0;
ctmoNew.WriteTotalTimeoutMultiplier = 0;
ctmoNew.WriteTotalTimeoutConstant = 0;
if (!SetCommTimeouts(hComm[port], &ctmoNew)) {
setBit(SystemState, SYSTEM_PORT_ERROR);
//ShowPortMessage(true, 24, port, "Cannot set serial port timeout information:");
if (!CloseHandle(hComm[port])) {
//ShowPortMessage(true, 22, port, "Cannot close serial port:");
}
hComm[port] = NULL;
return;
}
} else {
setBit(SystemState, SYSTEM_PORT_ERROR);
//ShowPortMessage(true, 25, port, "Cannot get serial port timeout information:");
if (!CloseHandle(hComm[port])) {
//ShowPortMessage(true, 22, port, "Cannot close serial port:");
}
hComm[port] = NULL;
return;
}
for (j = 0; j < 255; j++) {
if (!ReadFile(hComm[port], buff, sizeof(buff), &dwBytesRead, NULL)) {
setBit(SystemState, SYSTEM_PORT_ERROR);
//ShowPortMessage(true, 26, port, "Cannot read serial port:");
j = 999; //read error
break;
}
if (dwBytesRead == 0) //No data in COM buffer
break;
Sleep(10); //Have to sleep certain time to let hardware flush buffer
}
if (j != 999) {
setBit(pcState[port], PORT_OPEN);
}
} else {
setBit(SystemState, SYSTEM_PORT_ERROR);
//ShowPortMessage(true, 28, port, "Cannot open serial port:");
hComm[port] = NULL;
}
HANDLE TCommPorts::OpenCommPort(void) {
// OPEN THE COMM PORT.
if (hComm)
return NULL; // if already open, don't bother
if (systemDetect == SYS_DEMO)
return NULL;
hComm = CreateFile(port,
GENERIC_READ | GENERIC_WRITE,
0, //Set of bit flags that specifies how the object can be shared
0, //Security Attributes
OPEN_EXISTING,
0, //Specifies the file attributes and flags for the file
0);//access to a template file
// If CreateFile fails, throw an exception. CreateFile will fail if the
// port is already open, or if the com port does not exist.
// If the function fails, the return value is INVALID_HANDLE_VALUE.
// To get extended error information, call GetLastError.
if (hComm == INVALID_HANDLE_VALUE) {
// throw ECommError(ECommError::OPEN_ERROR);
return INVALID_HANDLE_VALUE;
}
// GET THE DCB PROPERTIES OF THE PORT WE JUST OPENED
if (GetCommState(hComm, &dcbCommPort)) {
// set the properties of the port we want to use
dcbCommPort.BaudRate = CBR_9600;// current baud rate
//dcbCommPort.BaudRate = CBR_115200;
dcbCommPort.fBinary = 1; // binary mode, no EOF check
dcbCommPort.fParity = 0; // enable parity checking
dcbCommPort.fOutxCtsFlow = 0; // CTS output flow control
dcbCommPort.fOutxDsrFlow = 0; // DSR output flow control
//dcbCommPort.fDtrControl = 1; // DTR flow control type
dcbCommPort.fDtrControl = 0; // DTR flow control type
dcbCommPort.fDsrSensitivity = 0;// DSR sensitivity
dcbCommPort.fTXContinueOnXoff = 0; // XOFF continues Tx
dcbCommPort.fOutX = 0; // XON/XOFF out flow control
dcbCommPort.fInX = 0; // XON/XOFF in flow control
dcbCommPort.fErrorChar = 0; // enable error replacement
dcbCommPort.fNull = 0; // enable null stripping
//dcbCommPort.fRtsControl = 1; // RTS flow control
dcbCommPort.fRtsControl = 0; // RTS flow control
dcbCommPort.fAbortOnError = 0; // abort reads/writes on error
dcbCommPort.fDummy2 = 0; // reserved
dcbCommPort.XonLim = 2048; // transmit XON threshold
dcbCommPort.XoffLim = 512; // transmit XOFF threshold
dcbCommPort.ByteSize = 8; // number of bits/byte, 4-8
dcbCommPort.Parity = 0; // 0-4=no,odd,even,mark,space
dcbCommPort.StopBits = 0; // 0,1,2 = 1, 1.5, 2
dcbCommPort.XonChar = 0x11; // Tx and Rx XON character
dcbCommPort.XoffChar = 0x13; // Tx and Rx XOFF character
dcbCommPort.ErrorChar = 0; // error replacement character
dcbCommPort.EofChar = 0; // end of input character
dcbCommPort.EvtChar = 0; // received event character
}
else
{
// something is way wrong, close the port and return
CloseHandle(hComm);
throw ECommError(ECommError::GETCOMMSTATE);
}
// SET BAUD RATE, PARITY, WORD SIZE, AND STOP BITS TO OUR SETTINGS.
// REMEMBERTHAT THE ARGUMENT FOR BuildCommDCB MUST BE A POINTER TO A STRING.
// ALSO NOTE THAT BuildCommDCB() DEFAULTS TO NO HANDSHAKING.
// wsprintf(portSetting, "%s,%c,%c,%c", baud, parity, databits, stopbits);
dcbCommPort.DCBlength = sizeof(DCB);
// BuildCommDCB(portSetting, &dcbCommPort);
if (!SetCommState(hComm, &dcbCommPort)) {
// something is way wrong, close the port and return
CloseHandle(hComm);
throw ECommError(ECommError::SETCOMMSTATE);
}
// set the intial size of the transmit and receive queues.
// I set the receive buffer to 32k, and the transmit buffer
// to 9k (a default).
if (!SetupComm(hComm, 1024*32, 1024*9))
{
// something is hay wire, close the port and return
CloseHandle(hComm);
throw ECommError(ECommError::SETUPCOMM);
}
// SET THE COMM TIMEOUTS.
if (GetCommTimeouts(hComm,&ctmoOld)) {
memmove(&ctmoNew, &ctmoOld, sizeof(ctmoNew));
//default settings
ctmoNew.ReadTotalTimeoutConstant = 100;
ctmoNew.ReadTotalTimeoutMultiplier = 0;
ctmoNew.WriteTotalTimeoutMultiplier = 0;
ctmoNew.WriteTotalTimeoutConstant = 0;
if (!SetCommTimeouts(hComm, &ctmoNew)) {
// something is way wrong, close the port and return
CloseHandle(hComm);
throw ECommError(ECommError::SETCOMMTIMEOUTS);
}
} else {
CloseHandle(hComm);
throw ECommError(ECommError::GETCOMMTIMEOUTS);
}
return hComm;
}

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