Manual BG41/BG42/BG43 Software
Rev. 99/49 4-15
ANZ
Number of the bytes, reserved for the buffer, in the reception DB. The buffer is
organised as a loop buffer, i.e. if the buffer is completely full, any further bytes
will be recorded once again at the start of the buffer.
FEHL
The bits of these bytes are set at 0, if functioning correctly. In the case of a
malfunction, an errror code will be entered. The error is acknowledged
immediately, i.e. the byte will be reset at 0 once the cause of the error has been
eliminated. Error 5 (buffer overflow) is to be acknowledged by the user.
An overview of possible error codes can be found in chapter 4.1.5.3.
NEUS
As long as the bit is at the signal state 1, the handling of the function block is
discontinued.
Management of write and read pointers
The handling of write and read pointers can be clarified by using two examples. The following is
required for this: the receive buffer begins from the data word DW 5 (parameter ANF) and the size
of the receive buffer (loop buffer) is 12 bytes (parameter ANZ).
Before data is received the write pointer (SZ) and the read pointer (LZ) point to DL5, the difference
is therefore 0. If, for example, 5 bytes are received from a peripheral device, they are recorded
alternately in data word left (DL) and data word right (DR).
The write pointer is increased by 1 for every byte received. After receiving 5 bytes, it therefore has a
value of 5 and points to the next free space in reception DB. Both evaluation possiblities are shown
in the following examples:
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