Cypress S6J3200 Series, Manual

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CHAPTER 32:Memory Protection Unit for AHB
1182 S6J3200 Series Hardware Manual Document Number: 002-04852 Rev. *G
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Steps in Programming the MPU AHB Module
Figure 5-1 Programmer’s Flowchart
1. After the system reset, the software detects the module ID number of the MPU AHB by reading the
MPUHn_MID register. This helps it in identifying the attributes and capabilities supported by the MPU
AHB module. The software then configures the MPU AHB by setting the appropriate registers.
2. By default, the MPU AHB propagates the MPUHn_CTRL0:NMI flag to the CPU through the Interrupt
Controller. If polling mode is desired, the software can reset the MPUHn_NMIEN:NMIEN bit to "0".
Note:
The MPUHm_NMIEN:NMIEN can be written only once after reset. Subsequent write accesses to this
bit have no visible impact on the state of this bit.
3. When the NMI is triggered (or in polling mode if the software detects during its polling cycle that the
MPUHn_CTRL0:NMI status flag is set), the CPU is invoked and reads the status information collected
and stored by the MPU AHB in its CSR.
4. The software diagnoses the information about the protection violation transaction and initiates a
corrective action (if any).
1.
2.
No
Yes
3.
4.
5.
NMI is set?
Read the transaction information
Take corrective action
Clear the NMI
Wait/poll for MPU AHB NMI
System reset
Read module ID and configure MPU AHB
Program the MPUHn_NMIEN:NMIEN