Commits on Oct 23, 2011

1. In some boards the serial hardware is wired in such a way that the re… …

   …ceiver
   
   is always enabled so
   everything you transmit gets back on the receive buffer, libmodbus thinks it is
   the slave answer and fails with a checksum error.
   
   I tried to fix it by disabling the receiver before transmitting with tcsetatrr and
   turning it back on after transmission but it didn't worked, the bytes were still
   echoed to the receive buffer. So finally I fixed it by reading from the port the
   same amount of bytes transmitted so they get out of the buffer.
   
   Added a new field to the modbus_rtu structure, added a couple functions and
   modified the rtu's transmit function. The new functions are:
   
   int modbus_rtu_set_echohw_mode(modbus_t *ctx, uint8_t mode);
   int modbus_rtu_get_echohw_mode(modbus_t *ctx);
   
   echohw mode can be one of MODBUS_RTU_NO_ECHOHW or MODBUS_RTU_HAS_ECHOHW. By default
   the RTU is in MODBUS_RTU_NO_ECHOHW which means it works as usual, but if you change
   it to MODBUS_RTU_HAS_ECHOHW then all the transmitted bytes will be taken out of the
   receive buffer.

   Jaime Alberto Silva committed Oct 23, 2011
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2. Fixed some macros that made compilation break on systems that don't d… …

   …efine
   
   HAVE_DECL_TIOCSRS485.

   Jaime Alberto Silva committed Oct 23, 2011
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   834dfea View commit details

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