forked from Archive/PX4-Autopilot
118 lines
5.9 KiB
Plaintext
118 lines
5.9 KiB
Plaintext
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apps/modbus README
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==================
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This directory contains a port of last open source version of FreeModBus
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(BSD license). The code in this directory is a subset of FreeModBus version
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1.5.0 (June 6, 2010) that can be downloaded in its entirety from http://developer.berlios.de/project/showfiles.php?group_id=6120.
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Directory Structure/Relation to freemodbus-v1.5.0
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-------------------------------------------------
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The original FreeModBus download consists of several directories. This
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subset takes only the contents of one directory, modbus/, that implements
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the core modbus logic and integrates that directory into the NuttX build
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system. The mapping between freemodbus-v1.5.0 and the nuttx directories
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is shown below:
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--------------------------- ----------------------------------------------
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freemodbus-v1.5.0 Nuttx
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--------------------------- ----------------------------------------------
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All top level .txt files Not included
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demo/ Not included. This directory contains demo
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and porting code for a variety of platforms.
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The NuttX demo was ported from the the LINUX
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demo in this director and can be found at
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apps/examples/modbus.
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doc/ Note included. This directory contains Doxygen
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support files.
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modbus/ Included in its entirety in various locations:
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ascii apps/modbus/ascii
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functions apps/modbus/functions
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include apps/include/modbus
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mb.c apps/modbus/mb.c
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rtu apps/modbus/rtu
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tcp apps/modbus/tcp
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tools/ Note included. This directory contain Doxygen
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tools.
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--------------------------- ----------------------------------------------
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So this directory is equivalent to the freemodbus-v1.5.0/modbus
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directory except that (1) it may include modifications for the integration
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with NuttX and (2) the modbus/include directory was moved to apps/modbus.
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The original, unmodified freemodbus-v1.5.0 was checked in as SVN revision
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4960.
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The other directory here, nuttx/, implements the NuttX modbus interface.
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It derives from the freemodbus-v1.5.0/demo/LINUX/port directory.
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Configuration Options
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=====================
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In the original freemodbus-v1.5.0 release, the FreeModBus configuration
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was controlled by the header file mbconfig.h. This header file was
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eliminated (post revision 4960) and the FreeModBus configuration
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was integrated into the NuttX configuration system.
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The NuttX-named configuration options that are available include:
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CONFIG_MODBUS - General ModBus support
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CONFIG_MB_ASCII_ENABLED - Modbus ASCII support
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CONFIG_MB_RTU_ENABLED - Modbus RTU support
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CONFIG_MB_TCP_ENABLED - Modbus TCP support
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CONFIG_MB_ASCII_TIMEOUT_SEC - Character timeout value for Modbus ASCII. The
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character timeout value is not fixed for Modbus ASCII and is therefore
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a configuration option. It should be set to the maximum expected delay
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time of the network. Default 1
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CONFIG_MB_ASCII_TIMEOUT_WAIT_BEFORE_SEND_MS - Timeout to wait in ASCII prior
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to enabling transmitter. If defined the function calls
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vMBPortSerialDelay with the argument CONFIG_MB_ASCII_TIMEOUT_WAIT_BEFORE_SEND_MS
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to allow for a delay before the serial transmitter is enabled. This is
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required because some targets are so fast that there is no time between
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receiving and transmitting the frame. If the master is to slow with
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enabling its receiver then he will not receive the response correctly.
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CONFIG_MB_FUNC_HANDLERS_MAX - Maximum number of Modbus functions codes the
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protocol stack should support. The maximum number of supported Modbus
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functions must be greater than the sum of all enabled functions in this
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file and custom function handlers. If set to small adding more functions
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will fail.
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CONFIG_MB_FUNC_OTHER_REP_SLAVEID_BUF - Number of bytes which should be
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allocated for the Report Slave ID command. This number limits the
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maximum size of the additional segment in the report slave id function.
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See eMBSetSlaveID() for more information on how to set this value. It
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is only used if CONFIG_MB_FUNC_OTHER_REP_SLAVEID_ENABLED is set to 1.
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CONFIG_MB_FUNC_OTHER_REP_SLAVEID_ENABLED - If the Report Slave ID
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function should be enabled.
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CONFIG_MB_FUNC_READ_INPUT_ENABLED - If the Read Input Registers function
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should be enabled.
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CONFIG_MB_FUNC_READ_HOLDING_ENABLED - If the Read Holding Registers
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function should be enabled.
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CONFIG_MB_FUNC_WRITE_HOLDING_ENABLED - If the Write Single Register
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function should be enabled.
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CONFIG_MB_FUNC_WRITE_MULTIPLE_HOLDING_ENABLED - If the Write Multiple
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registers function should be enabled.
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CONFIG_MB_FUNC_READ_COILS_ENABLED - If the Read Coils function should
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be enabled.
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CONFIG_MB_FUNC_WRITE_COIL_ENABLED - If the Write Coils function should
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be enabled.
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CONFIG_MB_FUNC_WRITE_MULTIPLE_COILS_ENABLED - If the Write Multiple Coils
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function should be enabled.
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CONFIG_MB_FUNC_READ_DISCRETE_INPUTS_ENABLED - If the Read Discrete Inputs
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function should be enabled.
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CONFIG_MB_FUNC_READWRITE_HOLDING_ENABLED - If the Read/Write Multiple
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Registers function should be enabled.
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See also other serial settings, in particular:
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CONFIG_SERIAL_TERMIOS - Serial driver supports termios.h interfaces (tcsetattr,
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tcflush, etc.). If this is not defined, then the terminal settings (baud,
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parity, etc.) are not configurable at runtime; serial streams will not be
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flushed when closed.
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Note
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====
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The developer of FreeModBus, Christian Walter, is still developing Modbus
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libraries, although they are now commercial. See
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http://www.embedded-solutions.at/ for further information.
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