module clock enabled through PCC CGC bit, there will not beany transfer error termination.3.4.1 Read-after-write sequence and required serialization ofmemory operationsIn some situations, a write to a peripheral must be completed fully before a subsequentaction can occur. Examples of such situations include:• Exiting an interrupt service routine (ISR)• Changing a mode• Configuring a functionIn these situations, the application software must perform a read-after-write sequence toguarantee the required serialization of the memory operations, as shown in the followingtable.Table 3-2. Read-after-write sequence to guarantee required serialization of memoryoperationsStep Action1 Write the peripheral register.2 Read the written peripheral register to verify the write.3 Continue with subsequent operations.NOTEOne factor contributing to these situations is processor writebuffering. The processor architecture has a programmableconfiguration field to disable write buffering:ACTLR[DISDEFWBUF]. (For details see Arm® Cortex® M4Processor Technical Reference Manual, Revision r0p1, at http://arm.com ). However, disabling buffered writes is likely todegrade system performance much more than simplyperforming the required memory serialization for the situationsthat truly require it.Chapter 3 Memory MapMWCT101xS Series Reference Manual, Rev. 3, 07/2019NXP Semiconductors 67
