Description of CEI-100/200 ARINC Interface
Transmitting Data
CEI-100/CEI-200/CEI-
x20 User’s Manual
166
channel are different, it knows it has to transmit data and does so. After
each word is transmitted, the slave updates the tail pointer.
Since it is very possible to stuff data in the transmit buffer faster than it
can be sent, check to see if the head pointer catches up to the tail pointer
before any data is put in the buffer. If the head pointer catches up, an
entire buffer of data is not sent.
If you have put data in a transmit buffer, wait until the head and tail
pointers are equal before resetting the board. The slave updates the tail
pointer after data has been removed from the buffer and put into the
transmitter and the transmitter has been started. This time does not exactly
coincide with the time the data goes out on the bus. It is starting to go out
on the bus at this point, and is completely out no more than 32 bit times
hence. (A bit time, of course, is determined by the programmed bit rate.)
The transmit buffer data structures are located at the following offsets and
take the same format as the receive buffers:
CEI-100 -
0440h
- transmitter 1
CEI-200 -
0470h
- transmitter 1
0478h
- transmitter 2
0480h
- transmitter 3
0488h
- transmitter 4
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com