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/* Introduction */
__TOC__
__TOC__
==Introduction==
FixmeBus is a field bus based on the half duplex RS485 famous hardware protocol. It is a master / slave architecture, with every slave chained together. The communication protocol has following parameters:
*38,400 bauds
*8 data bits
*1 start and 1 stop bit
*no parity
*no flow control
Each end of the bus is terminated with a 1% 120R resistor.
Every data frame on the bus is like this (byte on the left = first byte):
*2 bytes of slave adress (ID_HIGH and ID_LOW) => 65536 slave adress
**ID = 0 => Master
**ID = 65535 => order to all slaves (no ack)
**ID = 65000 to 65499 => order to a group of slave (no ack)
**ID = 1000 to 64999 => order to an unique slave (ack)
*2 bytes for the function (FCT_HIGH and FCT_LOW)
*1 byte for the number of data bytes to transmit (N_BYTE)
*n byte(s) of data (DATA) bytes (max. 200 bytes per frame)
*2 bytes for the CRC (CRC_HIGH and CRC_LOW)
{| class="wikitable" style="text-align: center; color: green;"
|b0
|b1
|b2
|b3
|b4
|b5
|...
|bn+4
|bn+5
|bn+6
|-
!ID_HIGH
!ID_LOW
!FCT_HIGH
!FCT_LOW
!N_BYTE
!DATA[0]
!...
!DATA[n-1]
!CRC_HIGH
!CRC_LOW
|}
==Technical information==
#[[Hardware]]
#[[Software]]
