COBHAM GR740 User Manual

GR740-UM-DS, Nov 2017, Version 1.7 370 www.cobham.com/gaisler
GR740
enabled, the value to be loaded into the ET counter must be written into the Command Elapsed Time
registers. The ARM bit field in the Status 0 register will set itself to ‘1’ when the first Command
Elapsed Time register is written. After the occurrence of the external enable signal the value will be
loaded into the ET counter and the ARM bit field in the Status 0 register will set itself to ‘0’. An inter-
rupt can also be generated when the ET counter is loaded, the corresponding interrupt (Set ET Exter-
nal Interrupt Enable) must be enabled.
31.3.12 Synchronisation of target using SpaceWire Time-Codes
Note: This functionality is only enabled in silicon revision 1.
It is possible to synchronise the target only using SpaceWire Time-Codes. A master sending Space-
Wire Time-Codes (using its Elapsed time counter) at regular interval can synchronise the Elapsed
time in the target. The frequency of Time-code transmission in the master and the frequency of (when
to expect a) Time-code in the target must match, this can be achieved by setting the Mapping fields in
the Configuration 0 register. The incoming SpaceWire Time-Codes and the Time-code position
mapped in the target Elapsed Time is compared, if they match the bits available after the compared
bits are made zero, if the local time map is less than one (External Time-code arrived early) then the
bits available after the compared bits are made zero and the other part (including the mapped part) is
incremented by one. If the above two cases occurred then the target time is in sync with the master
time and the Insync bit in Status 0 register is enabled. If the incoming Time-code is in out of order
(Non consecutive) then the synchronisation is stopped, the Insync bit in Status 0 register is disabled
(but the local time keeps running) and an interrupt is generated if corresponding interrupt (Non con-
secutive SpaceWire Time-code Interrupt) bit is enabled.
31.4 Registers
The core is programmed through registers mapped into AMBA APB address space.
Table 468.Registers
APB address offset Register
0x000-0x00F Configuration Field
0x000 Configuration 0
0x004 Configuration 1
0x008 Configuration 2
0x00C Configuration 3
0x010 - 0x01F Status Field
0x010 Status 0
0x014 Status 1
0x018 RESERVED
0x01C RESERVED
0x020 - 0x03F Command Field
0x020 Control
0x024 Command Elapsed Time 0
0x028 Command Elapsed Time 1
0x02C Command Elapsed Time 2
0x030 Command Elapsed Time 3
0x034 Command Elapsed Time 4
0x038 RESERVED
0x03C RESERVED
0x040 - 0x05F Datation Field

COBHAM GR740 Specifications

General

Brand	COBHAM
Model	GR740
Category	Computer Hardware
Language	English