Synchronizing Realview Ice; Figure 14-2 Realview Ice Clock Synchronization - ARM ARM1176JZF-S Technical Reference Manual

14.2

Synchronizing RealView ICE

RealView ICE
interface pads
nTRST
TDO
RTCK
RealView
ICE
TCK
TMS
TDI
JTAGSYNCBYPASS
ARM DDI 0301H
ID012310
The system and test clocks are synchronized internally to the macrocell. The ARM RealView
ICE debug agent directly supports one or more cores within an ASIC design. The off-chip
device, for example, RealView ICE, issues a TCK signal and waits for the RTCK, Returned
TCK, signal to come back. Synchronization is maintained because the off-chip device does not
progress to the next TCK edge until after an RTCK edge is received. Figure 14-2 shows this
synchronization.
ARM1176JZ-S core
DBGnTRST
DBGnTDOEN
DBGTDO
D
CLKIN
CLKIN
Note
All of the D type flip-flops are reset by DBGnTRST.
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Q D Q D Q D Q
CLKIN
Input sample and hold

Figure 14-2 RealView ICE clock synchronization

Debug Test Access Port
0
DBGTCKEN
TCK
1
EN
D Q 0
DBGTMS
TMS
1
EN
D Q 0
DBGTDI
TDI
1
14-3