NXP Semiconductors MPC5644A, Reference Manual, Page: 689 / 1735

Reaction Module (REACM)
MPC5644A Microcontroller Reference Manual, Rev. 6
Freescale Semiconductor 689
Chapter 23
Reaction Module (REACM)
23.1 Introduction
The Reaction Module (REACM) is composed of 6 channels. Each channel contains three outputs. The
primary application of this module is in the area of solenoid control for direct injection systems, valve
control in automatic transmissions and others. It is connected to the on-chip ADC which monitors the
current on the solenoid or valve. Based on that the reaction channel generates a PWM signal that modulates
the current circulating in the solenoid or valve. It is a cost effective solution due to extensive sharing of
several resources among channels and parameterized register banks for adequate dimensioning of
resources and functionality.
23.1.1 Features
The REACM features include:
• Per-channel architecture for independent output control
• Interface with on-chip ADC for fast response times
• Hardware connection with on-chip timer channels with channel routing capability
• Innovative concept of Shared Modulation Control
• Innovative concept of dynamic timer allocation
• 3 outputs per channel to support different driver architectures
• Flexibility to operate based on timing and threshold
• On-the-fly capture of ADC result reference for fast calibration
• Open and short circuit monitoring capability
Note:DMA is not supported in Andorra devices.
23.1.2 Modes of operation
23.1.2.1 Programing Mode
After a reset is applied, the reaction module is in programming mode. In this mode all channels are
disabled and outputs are at logic zero. Note that this state does not necessarily mean that zero is the neutral
state for the channel load, so care must be taken in order to disconnect the channel from the load in this
case.
In the programming mode the host CPU writes all module parameters including:
1. Modulation word data (see Section 23.4.2, Modulation control words bank )
2. Channel control data (see Section 23.3.7, REACM Channel n Configuration Register
(REACM_CHCRn) )
3. Threshold data (see Section 23.3.12, REACM Threshold Bank Register (REACM_THBK) )
4. Timer bank data (see Section 23.3.10, REACM Shared Timer Bank Registers (REACM_STBK) )