NXP Semiconductors MPC5644A, Reference Manual, Page: 848 / 1735

Enhanced Time Processing Unit (eTPU2)
MPC5644A Microcontroller Reference Manual, Rev. 6
848 Freescale Semiconductor
IPACA,IPACB and OPACA,OPACB – Input and Output Pin Action Control Registers
These registers determine the transition detections and output pin actions which takes place due to match
or transition events. Each field is three bit wide. After reset, the IPACA/B and OPACA/B registers are set
to 000. IPACA and IPACB registers are mutually independent and have identical encoding, and so do
OPACA and OPACB.
Table 24-44 shows IPAC and OPAC encoding. Note that transition detections are
independent from the output actions, but some options of output actions are triggered by transition
detections. Output actions can also be triggered by Matches. For a detailed definition of Transition
Detections, see
Section 24.5.5.3, Transition Detection and Time Base Capture .
IPACA/B define the Transition events treated by channel logic. Although the name “transition” is
generically used for the transition detections, IPAC options 100 and 101 do not really detect transitions:
they actually sample the state of the input signal at the occurrence of the corresponding Match (Match A
used for IPACA, Match B used for IPACB).
PSTI flag test on branch no no BCC 0
PSTO flag test on branch, write no immediate BCC (test)
PSC, PSCS (set)
0
OBE write only no immediate TBSA values
1000,1001
0
(negated)
PSS flag test on branch on CHAN
assignment
no BCC n.a.
2
PRSS flag test on branch on CHAN
assignment
no BCC n.a.
3
1
See Section 24.5.9, Microinstruction set .
2
PSS is PSTI or PSTO sampled on CHAN assignments and at thread start.
3
PRSS is PSTI sampled on channel service request.
Table 24-44. IPACA/B and OPACA/B Encoding
Value IPAC meaning OPAC meaning
000 Do not detect transitions Do not change output signal
001 Detect rising edge only Match
1
sets output signal high
010 Detect falling edge only Match
1
sets output signal low
011 Detect either edge Match
1
toggles output signal
100 Detect input signal = 0 on Match
1
1
Match A is used for IPACA/OPACA, and Match B for IPACB/OPACB.
Transition sets output signal low
101 Detect input signal = 1 on Match
1
Transition detection sets output signal high
110 reserved Transition detection toggles output signal
111 n.a.
2
n.a.
2
Table 24-43. Pin Control Registers microcode accesses
Register Access Type
Sampled
from channel
Update to
channel
Microcode
fields
1
Reset
value