MPC563XM Reference Manual, Rev. 1
766
Freescale Semiconductor
Preliminary—Subject to Change Without Notice
Figure 23-26. ETPUCxHSRR Register
HSR[2:0] — Host Service Request
This field is used by the Host CPU to request service to the channel (see
)
HSR = 000: no Host Service Request pending
HSR > 000: function-dependent Host Service Request pending.
HSR value turns to 000 automatically at the end of microengine service for that channel, but only if the
thread started due to an HSR. Host should write HSR>0 only when HSR=0. Writing HSR=000 withdraws
a pending request if scheduler did not begin to resolve the Entry Point yet, but it does not abort the service
thread from that point on. For more details, see
Section 23.4.1.1, “Entry Points
.
23.4
Functional Description
23.4.1
Functions and Threads
eTPU processing is event-driven, in the sense that eTPU microcode only runs to service a request from an
event. Service Requests may result from the occurrence of any of the following events:
•
Host CPU writing a non-zero value to the channel HSR (Host Service Request) field in
ETPUCxHSR register.
•
occurrence of a time base match, an input signal transition, or a specific combination of them
(depending on the Channel Mode currently configured).
•
a Link Service Request.
A given event is always associated to only one Channel:
•
There is one HSR register field for each Channel
•
Each signal is associated with only one Channel, which has its own Match registers and
independent mode configuration.
Channel_Registe 0x8
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
R
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
RESET:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
R
0
0
0
0
0
0
0
0
0
0
0
0
0
HSR
W
RESET:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
= Unimplemented or Reserved