NXP Semiconductors MPC5644A, Reference Manual, Page: 812 / 1735

Enhanced Time Processing Unit (eTPU2)
MPC5644A Microcontroller Reference Manual, Rev. 6
812 Freescale Semiconductor
unused area of the Entry Table. For this purpose, Function numbers should be selected from 0 up to 31. If,
for example, only 8 functions are implemented, only the Entry Table locations for Functions 0 to 7 are
used, and the Entry Table locations for functions 8 to 31 can be used as microinstruction memory (adding
extra continuous 1536 bytes for microprogram usage).
One way of implementing different sets of Functions is having more than one Entry Table, and configuring
the eTPU with the appropriate one for the application by changing field ETPU_ECR[ETB]. Note that the
engines can use different Entry Tables, with or without the same set of Functions.
24.5.1.1.2 Entry point address generation
The Entry Point address within the Entry Table is determined by the Function assigned to the Channel, the
state of the Channel, the type of event, and the condition encoding scheme. Together with the Entry Table
base address, they form the Entry Point Address at the SCM, as shown in
Figure 24-25 .
Figure 24-25. Entry Point Address (host address offset)
The type of event and channel state are coded in the Encoded Channel Conditions field C[4:0], according
to one of two encoding schemes:
• Standard Entry Table Condition encoding scheme, shown in Table 24-36 , which privileges Host
Service Requests.
• Alternate Entry Table Condition encoding scheme, shown in Table 24-37 , which focus on other
events and state decoding.
The events that take part on condition encoding generate a Service Request, and have four origins:
1. Match Recognition (caused by greater/equal match, or equal-only, between the value TCR1/2 and
the value stored in the channel match registers). eTPU channels support single and double match
in various modes of match recognition; see
Section 24.5.5.2, Match Recognition .
2. Transition Detect Service Request (channel input signal transition detection of a selected edge).
The eTPU channels support single and double transition, which together with the double match
options provide various modes of transition detection; see
Section 24.5.5.3, Transition Detection
and Time Base Capture .
3. Channel Linking Service Request (microcode writing the channel number to the LINK register).
Link service request allows one channel to activate another (see Section 24.5.5.5, Channel Link ).
4. Host Service Request (Host writes a non-zero value to the HSR bits of the channel; see
Section 24.5.2.5, Host service requests ).
ETB[4:0]
(ETPU_ECR)
(ETPU_CxCR)
Encoded
(C4-C1)
Channel
Conditions CFS[4:0]
Encoded
(C0)
Channel
Conditions
A5-A2 A10-A6
A1
A15-A11
Half-word Select Word Address
A0 = 0