eMBMasterRegHoldingCB() function

Callback function used if a Holding Register value is read or written by the protocol stack. The starting register address is given by \c usAddress and the last register is given by usAddress + usNRegs - 1.

Syntax

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Summary

Declaration

Definition

from mb_m.h:327

eMBErrorCode eMBMasterRegHoldingCB( UCHAR * pucRegBuffer, USHORT usAddress, USHORT usNRegs, eMBRegisterMode eMode );

Implemented in esp_modbus_master.c:212

Arguments

Argument

Description

pucRegBuffer

If the application registers values should be updated the buffer points to the new registers values. If the protocol stack needs to now the current values the callback function should write them into this buffer.

usAddress

The starting address of the register.

usNRegs

Number of registers to read or write.

eMode

If eMBRegisterMode::MB_REG_WRITE the application register values should be updated from the values in the buffer. For example this would be the case when the Modbus master has issued an WRITE SINGLE REGISTER command. If the value eMBRegisterMode::MB_REG_READ the application should copy the current values into the buffer \c pucRegBuffer.

Return value

The function must return one of the following error codes: - eMBErrorCode::MB_ENOERR If no error occurred. In this case a normal Modbus response is sent. - eMBErrorCode::MB_ENOREG If the application does not map an coils within the requested address range. In this case a ILLEGAL DATA ADDRESS is sent as a response.

Examples

References

from examples

eMBMasterRegHoldingCB() function

Syntax

Arguments

Return value

Examples

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