/* ----------------------- Start implementation -----------------------------*/
eMBErrorCode
eMBMasterRTUInit(RS485_NUM RS485_X, ULONG ulBaudRate, eMBParity eParity )
{
eMBErrorCode eStatus = MB_ENOERR;
ULONG usTimerT35_50us;
OS_CPU_SR cpu_sr;
ENTER_CRITICAL_SECTION( );//¹ØÖжÏ
/* Modbus RTU uses 8 Databits. */
if( xMBMasterPortSerialInit( RS485_X, ulBaudRate, 8, eParity ) != TRUE )
{
eStatus = MB_EPORTERR;
}
else
{
/* If baudrate > 19200 then we should use the fixed timer values
* t35 = 1750us. Otherwise t35 must be 3.5 times the character time.
*/
if( ulBaudRate > 19200 )
{
usTimerT35_50us = 35; /* 1800us. */
}
else
{
/* The timer reload value for a character is given by:
*
* ChTimeValue = Ticks_per_1s / ( Baudrate / 11 )
* = 11 * Ticks_per_1s / Baudrate
* = 220000 / Baudrate
* The reload for t3.5 is 1.5 times this value and similary
* for t3.5.
*/
usTimerT35_50us = ( 7UL * 220000UL ) / ( 2UL * ulBaudRate );
}
if( xMBMasterPortTimersInit( ( USHORT ) usTimerT35_50us ) != TRUE )
{
eStatus = MB_EPORTERR;
}
}
EXIT_CRITICAL_SECTION( );//¿ªÖжÏ
return eStatus;
}
/* ----------------------- Start implementation -----------------------------*/
eMBErrorCode
eMBMasterRTUInit(UCHAR ucPort, ULONG ulBaudRate, eMBParity eParity )
{
eMBErrorCode eStatus = MB_ENOERR;
ULONG usTimerT35_50us;
ENTER_CRITICAL_SECTION( );
// инит USART порта 8бит режиме для MODBUS
if( xMBMasterPortSerialInit( ucPort, ulBaudRate, 8, eParity ) != TRUE )
{
eStatus = MB_EPORTERR;
}
else
{
// если скорость выше 19200 то используем фиксированную t3.5 = 1750us
if( ulBaudRate > 19200 )
{
usTimerT35_50us = 35; /* 1800us. */
}
else
{
/* The timer reload value for a character is given by:
*
* ChTimeValue = Ticks_per_1s / ( Baudrate / 11 )
* = 11 * Ticks_per_1s / Baudrate
* = 220000 / Baudrate
* The reload for t3.5 is 1.5 times this value and similary
* for t3.5.
*/
usTimerT35_50us = ( 7UL * 220000UL ) / ( 2UL * ulBaudRate );
}
// инит таймера тля отсчета t3.5
if( xMBMasterPortTimersInit( ( USHORT ) usTimerT35_50us ) != TRUE )
{
eStatus = MB_EPORTERR;
}
}
EXIT_CRITICAL_SECTION( );
return eStatus;
}
