SuperH (SH) 64-bit RISC Series SH-5 System Architecture, Volume ...

PRELIMINARY DATA
Key concepts 21
1.2.8 Chain latches
SH-5 provides a series of chain-latches. Chain-latches allow watchpoint hits, in the
WPC or bus analyzers, to enable or disable any other watchpoints.
Chain latches consist of an item of state, which is either set or clear. No assumptions
are made about the type of sequential device which will be used in the
implementation. Figure 1 shows a functional block diagram of the chain-latches.
IAx
Watchp
oint
Address
comparison
valid
Set
Clear
Full hit
WPC.
CHAIN_x
Other WP
pre-conditions
WPC
chain-latch set/
cleared by
WPC
watchpoint hit
action
&
Set
WPC.IA_C
HAIN_x
Clear
Select one
chain-latch
&
WPC
watchpoint
enable
WP Hit
Actions
D R A FT
Repeat for all
other WPC
watchpoints
dm_trin_n pin
+
Shared
chain-latch
Set
Clear
DM.
CHAN_x
Shared
chain-latch can
be set/cleared
by any
watchpoint hit
action
OR
Other WP
pre-conditions
Set
TRIG_IN
LATCH
Clear
Select one
chain-latch
&
bus analyzer
watchpoint enable
WP Hit
Actions
Repeat for all other
bus analyzer
watchpoints
Chain-latches in WPC
Chain-latches in DM
Figure 1: Chain-latch concept
05-SA-10003 v1.0
SuperH, Inc.
SH-5 System Architecture, Volume 3: Debug