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Reaction Module (REACM)
At point b, phase B is initiated by the threshold being achieved from phase A. CH0 increments the
Modulation Word address to MODULATION_ADDR = 0x1 and the second Modulation Word is read by
the channel. As a result of the second Modulation Word decoding the Vboost voltage is disabled causing
a peak modulation with Vbatt. The phase is called the Peak Vbatt phase. For phase B a
Threshold-Threshold modulation is used with levels I2 and I3 during a period defined by TB. Please see
Figure
23-39.
A timeout event is received from the Shared Timer submodule and a new Modulation Word is read. Phase
C corresponds to the recirculation phase. Energy from the injector is transferred back to the boost circuitry.
In this phase the current can not be measured because there is no current flowing through the sensor
resistor. A Threshold-Threshold modulation mode is used. The Shared Timer is started at the beginning of
this phase and TD delay is measured. The channel outputs are kept in the OFF state.
When the Shared Timer times out after TD delay the Modulation Word address is incremented,
MODULATION_ADDR = 0x4 and the Hold phase is initiated. This phase is typically longer compared to
the other phases and defines the amount of fuel that will be injected. Threshold-Threshold modulation
mode is used between levels I4 and I5 and Vbatt is selected as the power supply. The phase ends based on
the eTPU time window switching to off at point e. At this time the channel outputs are set to OFF and the
channel points to MODULATION_ADDR = 0x0 which is the address of the first Modulation Word. Note
that this address is not necessarily 0x0.
This modulation process is executed by a sequence of Modulation Words as described in
Modulation Control Words REACM_MCW, see
0
1
2
3
4
Fields
L
I
MM
PhaseA
0
1
00
Phase B
0
0
00
Phase C
0
0
00
Phase D
0
0
00
1
Any value
23.10.1 Advancing modulation phase on a threshold level
The Modulation Phase may be set to advance when a specific threshold value is reached. The use case for
this scenario is described in
achieved before the reaction channel advances to the next modulation phase, thus making sure that the
solenoid had the fastest opening speed.
742
Figure 23-20
5
6
7
8
9
10
11
12
13
SM
HOD
11
111
01
011
01
000
00
011
Figure 23-39. Modulation words for injector application
Figure
23-40. This functionality is used to assure a specific current level was
MPC5644A Microcontroller Reference Manual, Rev. 6
14
15
16
17
18
19
20
21
22
LOD
THRESHPT
101
000010 (I0)
000011 (I1)
001
000010 (I2)
000011 (I3)
1
000
X
001
000100 (I4)
000101 (I5)
Figure
23-39.
23
24
25
26
27
28
29
30
31
STPT
HDOFFPT
0001 (TB)
X
0010 (TC)
X
0011 (TD)
X
X
X
Freescale Semiconductor
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