The FPGA prescaler register address is incorrectly defined in the header file SMM_MPS2.h
This file is used in all Arm test software for MPS2, such as selftest, shieldtest, demo etc. The same header file is also used in MBED base code for MPS2.
The incorrect file defines the following register offsets:
RESERVED; // Offset: 0x01CPRESCALE; // Offset: 0x020 PSCNTR; // Offset: 0x024
In order to use the prescaler feature on MPS2, SMM_MPS2.h will need to be edited locally such that these offsets are correctly defined as:
PRESCALE; // Offset: 0x01C PSCNTR; // Offset: 0x020RESERVED; // Offset: 0x024