Enhanced Time Processing Unit (eTPU2)
29-58
Freescale Semiconductor
PXR40 Microcontroller Reference Manual, Rev. 1
Figure 29-28. Priority Passing Example
Examples of priority passing are shown in
. Each cycle contains seven time slots (or less if
no service request exist). In cycle B, no high-level or middle-level service requests are present before time
slot three which is assigned by default to high-level priority. Thus, time slot three is passed to the low level.
In cycle B there are also no middle-level service requests before time slot six, so it passes the priority to a
requesting high-level channel. During time slot six no more high level requests are left, but two new
middle-level requests arrive, and there are also three low level pending service requests. Thus, time slot
seven of cycle B and time slot one of cycle C are passed to the middle-level which is the next priority level
after high. Time slots two and three of cycle C are passed to the low level which contains the three
remaining channel service requests. At time slot three of cycle C the last low level request is serviced, and
the Scheduler passes to idle state. At this point the cycle C is truncated and the Scheduler passes to time
slot one of cycle D.
SLOT Number
6
7
1
2
3
4
5
6
1
2
3
1
M
H
H
M
H
L
H
M
H
H
M
H
H
High Pend Count
Service High
2
1
0
1
0
2
0
- X New Service Requests Arrive at a Specific Priority Level
2
0
X
2
2
2
1
1
1
0
0
0
1
2
2
1
0
2
2
7
DH
DM
DH
H>L
DL
DH
M>H
DM
H>M
H>M
M>L
H>L
1
0
DH, DH, DL - Default Service High, Middle or Low
H>L, H>M, M>H, M>L - Priority Passing Scheme
ID - Idle (no service request)
ID
Slot Assignment
SLOT ASSIGNMENTS:
Reset Slot
Fixed Priority Level
Middle Pend Count
Service Middle
Low Pend Count
Service Low
Number
Cycle A
Cycle B
Cycle C (truncated)
Cycle D
2
3
M
H
1
1
1
1
0
1
1
0
0
1
H
H>M
DM
DH
1
H
ID
Summary of Contents for PXR4030
Page 1: ...PXR40 Microcontroller Reference Manual Devices Supported PXR4030 PXR4040 PXR40RM Rev 1 06 2011...
Page 30: ...PXR40 Microcontroller Reference Manual Rev 1 Freescale Semiconductor xxx...
Page 40: ...PXR40 Microcontroller Reference Manual Rev 1 xl Freescale Semiconductor...
Page 66: ...Memory Map PXR40 Microcontroller Reference Manual Rev 1 2 4 Freescale Semiconductor...
Page 120: ...Signal Descriptions 3 54 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Page 860: ...FlexCAN Module 24 50 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Page 1167: ...Decimation Filter Freescale Semiconductor 28 53 PXR40 Microcontroller Reference Manual Rev 1...
Page 1168: ...Decimation Filter 28 54 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...