NXP Semiconductors MPC5644A, Reference Manual, Page: 693 / 1735

Reaction Module (REACM)
MPC5644A Microcontroller Reference Manual, Rev. 6
Freescale Semiconductor 693
Figure 23-3 shows the reaction module internal architecture. The channels are controlled by a Modulation
Control Word provided by the Modulation Control Bank submodule. The Modulation Word has
information about the type of modulation to be executed as well as the addresses for the Threshold and
Timer banks. The channel stores information such as the address of the modulation word and initial values
for the output pins after the channel is
enabled .
Note that the modulation process only initiates after the channel is moved to the active state. The following
sections describe this process in more detail.
After the activation, the channel sets the outputs with a predefined value stored in the REACM Channel n
Configuration Register (REACM_CHCRn). Only after this initialization process is the channel ready to
start a modulation process. Note that the channel only considers an ADC result as valid if it is within a
window defined by the timer input, usually connected to the on-chip eTPU. The reaction channel can
access more than one modulation word by incrementing the internal MODULATION_ADDR field in the
REACM_CHCRn. The original value of this field is preserved, thus when a new modulation cycle is
initiated the same modulation address value may be used.