Using these registers, which are designated as Output MTU, the data to be sent are transferred to the module.
By using the control bytes, the information required to put back together the sent frame from the individual Output MTU blocks is transferred to the superordinated module.
|
Bit |
Description |
|---|---|
|
0–5 |
0–63 = Segment length |
|
6 |
0 = Control byte for the next segment in a new MTU (TxByte1) 1 = Control byte for the next segment follows immediately after the segment end |
|
7 |
0 = Frame is not finished 1 = Frame is finished |
This length specification describes the length of the frame to be sent. However, only six bits are available in the control byte, thus 63 is the largest possible partial length here. If the frame to be sent is longer than the maximum segment length, it must be split to several segments with the corresponding control bytes. The real frame end is transferred to the module by bit 7 in the last segment.
With this information, it is transferred at which position the next control byte is to be expected.
Also see Multiple Segments / Segment Size.