COMPONENT MAINTENANCE MANUAL
C17004
34-57-96
Page 32
COPYRIGHT
SEXTANT Avionique 1995
c
(b)
µ
p bus interface
This interface is used to:
- Create selection read and write orders for the various TS25 pro-
grammable functions, upon command from the 68020
µ
p,
- Manage interrupt logic,
- Perform discrete management of outputs P104 and P106,
The
µ
p bus interface is connected to the data bus (D 16/31), address
bus (A1/9), SB service bus that also includes the signals for "chips
select" and interrupt.
(c) Function codes
This function is designed to generate and check one code per C/A
channel, based on instructions supplied by the data bus; the 68020
µ
p is used to check these codes for each channel (0 to 4).
The following programmable parameters are transmitted to the TS25
acquisition blocks:
- The pseudo distance
- The air speed code
- The choice of satellite
- The code word
- The delay advance step (deviation of the codes from the so-called
normal code),
- The type of correlation.
(d) Sequencer and Time Stamping Function
This function is designed to generate:
- The synchronization signals required by the various TS25 operators
and by the transfer between the TS25 and the 68020
µ
p, from the
H25 clock; the sequencing is organized into work cycles:
. channel cycle
. computation cycle
. last cycle before interrupt.
- Generation of a time stamp for an external event (EVTA or EVTB
signal) based on the most recent internal time base (BT signal).
MAY 30/95
The document reference is online, please check the correspondence between the online documentation and the printed version.
