Bosch TTCAN User Manual
Page 37
User’s Manual
BOSCH
- 37/77 -
Revision 1.6
TTCAN
11.11.02
manual_about.fm
3.5.19 TT Global Time Preset Register (addresses 0x65 & 0x64)
GTDiff
Global Time Preset
0x0000-0x7FFF Master_Ref_Mark = Master_Ref_Mark + GTDiff.
0x8000
reserved.
0x8001-0xFFFF Master_Ref_Mark = Master_Ref_Mark - (0x10000-GTDiff).
The Global Time Preset takes effect when the node is the current Time Master and when ‘1’ is
written to SGT in the TT Clock Control register. The next Reference Message will be
transmitted with the modified Master_Ref_Mark and with Disc_Bit = ‘1’, presetting the Global
Time in all nodes simultaneously.
GTDiff is reset to 0x0000 each time a Reference Message with Disc_Bit = ‘1’ becomes valid
or if the node is not the current time master.
GTDiff is locked (and WGTD is ‘1’) after setting SGT until the Reference Message with
Disc_Bit = ‘1’ becomes valid or until the node is no longer the current time master.
3.5.20 TT Clock Control Register (addresses 0x67 & 0x66)
ldSDL
ld(Synchronisation Deviation Limit)
0x0-0x7
Synchronisation Deviation
≤
2
(ldSDL + 5)
.
QCS
Quality of Clock Speed
one
SD
≤
SDL (always true in TTCAN Level 1).
zero
Local clock speed not synchronised to Time Master clock speed.
QGTP
Quality of Global Time Phase
one
Global Time in phase with Time Master.
zero
Global Time not valid (always true in TTCAN Level 1).
ECAL
Enable Clock Calibration
one
The automatic clock calibration in TTCAN Level2 is enabled.
zero
The automatic clock calibration in TTCAN Level2 is disabled.
EGTF
Enable Global Time Filtering
one
The Global Time filtering in TTCAN Level2 is enabled.
zero
The Global Time filtering in TTCAN Level2 is disabled.
ELT
Enable Local Time
one
The Local Time is enabled.
zero
The Local Time is stopped (default after hardware reset).
Note :
ELT can only be written during Configuration Mode. It may not be set before the TUR configura-
tion registers are programmed. Once the Local Time is started, is remains active until the CPU
writes ELT to ‘0’ or until the next hardware reset. Local Time is also started by resetting Init in
the CAN Control register.
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
GTDiff
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ldSDL
QCS QGTP ECAL EGTF ELT
TMC
DET
ECS
SWS
WGTD SGT
rw
r
r
rw
rw
rw
rw
rw
rw
rw
r
rw