Texas Instruments 990 User Manual page 249

Communications Structures
0.6.1 Download by Secondary Request
When the download operation is automatically accomplished the
following sequence of events occurs:
1. The host polls the secondary station.
2. The secondary station sends a download request (RIM).
3~
The
host·~ends
the first frame containing program data
(UI) •
4 .• The secondary station acknowledges (UA).
5. The host sends the second frame containing program data
(UI) •
6. The secondary station acknowledges (UA).
This continues until the download completes.
The sequence is shown in the following diagram:
HOST POLL~
FLAG ADDRo CMD.
0 . 0 0 0
CRC FLAG
4 RIM
FLAG ADDR. >17 CRC FLAG
Ul
..
I
FLAG ADDRo
>13
DATA CRC FLAG
4 UA
FLAG ADDRo >73 CRC FLAG
ETC
2280628
2270526-9701
0-15