Posted on June 05, 2017 at 13:59I am trying to implement a Modbus sever on the STM32f746 Nucleo.
- LWIP is running
- Cache is enabled
- MPU is protecting 2 areas as non cacheable, one for the ethernet descriptors, the other one for my variables
- Socket Server is running on port 80
I added the Freemodbus1.5 library files to the project and started a standard Modbus Task.
void vMBServerTask( void *arg )
{
eMBErrorCode xStatus;
portTickType xTicks;
pppSetAuth( PPPAUTHTYPE_NONE, NULL, NULL ); // TO DO clean code and remove this
for(;;)
{
if(eMBTCPInit( MB_TCP_PORT_USE_DEFAULT ) != MB_ENOERR )
{
printf('can't initalize modbus stack!\r\n' );
}
else if( eMBEnable( ) != MB_ENOERR )
{
printf('can't enable modbus stack!\r\n' );
}
else
{
eMBEventType eEvent=EV_READY;
xMBPortEventPost(eEvent); //Just a saty test
do
{
/* Application code here. */
xStatus = eMBPoll();
/* Update input registers with the current system tick. */
xTicks = xTaskGetTickCount( );
/* Note: little endian stuff */
usRegInputBuf[0] = ( USHORT ) ( xTicks );
usRegInputBuf[1] = ( USHORT ) ( xTicks >> 16UL );
}
while( ( xStatus == MB_ENOERR )/* && ( ePPPThrCtlCur == CONNECTED ) */);
( void )eMBDisable( );
( void )eMBClose( );
}
}
}
Code compliles fine but in portvent.c where I needed to update the call
xMailBox = sys_mbox_new( ); //this call is outdated
with
if (sys_mbox_new( &xMailBox, 8)!=ERR_OK)
{
printf ('Failed to init Mailbox');
return (FALSE);
}
else
{
printf ('Mailbox Init OK');
return (TRUE);
}
Modbus connection works fine.
The issue arises when sending a MODBUS request
1- The stack works fine, connection is accepted and the callback
prvxMBTCPPortReceive(...)
is called when I request data from my pc.
This funciton in turn calls
sys_mbox_post( xMailBox, &eMailBoxEvent );
that shows no problems and returns osOK.
Now the task polls the Mailbox
uiTimeSpent = sys_arch_mbox_fetch( xMailBox, &peMailBoxEvent, MB_POLL_CYCLETIME );
returns a timeout, so no messages. The posted message apparently disappeared making my efforts nonsense.
I am working with TRUE Studio.
Hope somebody can help me..
Fabio
