Texas Instruments 990 User Manual page 250

Communications Structures
D.6.2 Download by User (SCI) Request
When the download operation is requested by the use of the SCI
command DOWNLOAD the following sequence of events occurs:
1. The host sends an initialization command (SIM) to the
secondary station.
2. The secondary station acknowledges (UA).
3.
The host sends 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 eUA).
This continues until the download completes.
The sequence is shown in the following diagram:
SIM
FLAG
ADDR. >17 CRC FLAG
UA
FLAG
ADDR. >73 CRC
FLAG
UI
•
FLAG >13
DATA
I
ADDR.
CRC
FLAG
UA
..
FLAG ADDR. >73 CRC
FLAG
UI
I
•
FLAG
ADDR.
>13
DATA CRC FLAG
UA
..
FLAG
ADDR.
>73
CRC
FLAG
ETC
2280629
D-16
2270526-9701