Cortex-M3 Processor Overview and Debug Features
UG0331 User Guide Revision 15.0
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2.7.1.1
Memory Protection Unit
The MPU can be enabled by the selection option provided, as shown in the preceding figure. The
following table lists all the registers that can be used to configure the MPU for the creation of the
protected memory regions and setting the privileges for the created memory region in the firmware.
2.7.1.2
SysTick Timer Configuration
The SysTick timer can be configured using the Libero software, as shown in the
page 16, for
the SysTick calibration value; which is the rollover value of the internal SysTick timer, and SysTick clock
frequency as the division (4, 8, 16, or 32) of Cortex-M3 clock. This value is loaded into the
STCLK_DIVISOR register and it has to be configured to make sure that the SysTick clock frequency is
less than half of the frequency of Cortex-M3. SysTick also can be configured using the firmware by using
the following register, as depicted in the following table
2.7.1.3
Events Configuration
TXEV and RXEV event signals of the Cortex-M3 processor can be exposed to the FPGA fabric. This can
be configured using the Libero software, as shown in
2.7.1.4
System Power Management Configuration
The Cortex-M3 processor provides various power modes. M3_CLK is gated off when in SLEEPING or
SLEEPDEEP mode. SLEEPING and SLEEPDEEP signals are available at the FPGA fabric interface.
Sleep mode extension handshake signals are available at the FPGA fabric interface. System power
management options can be configured as shown in
2.7.1.5
Trace Port Interface Unit (TPIU) Configuration
TRACECLK & TRACEDATA[3:0] can be exposed to the FPGA fabric. TACECLK can be configured for
these signals by using the Libero software, as shown in the
Note:
If the user design is using the FPGA fabric based master, the Cortex-M3 processor requires a valid
program in eNVM (from eNVM start address 0x60000000) to execute at power-up or power-on reset.
The valid program can be a simple user boot code or a simple loop program. You can select a .hex file of
a valid program for eNVM data client using the SystemBuilder.
Table 5 •
MPU Configuration Register
Name of Register
Access Type
Address
Reset Value
MPU type register
Read Only
0xE000ED90
0x800
MPU control register
Read/Write
0xE000ED94
0x0
MPU region number
Read/Write
0xE000ED98
NA
MPU region base address
Read/Write
0xE000ED9C
NA
MPU region attribute and size
Read/Write
0xE000EDA0
NA
Table 6 •
SysTick Configuration Register
Name of Register
Access Type
Address
Reset value
SysTick Control & Status
Read/Write
0xE000E010
0x0
SysTick Reload value
Read/Write
0xE000E014
Unpredictable
SysTick Current Value
Read/Write clear
0xE000E018
Unpredictable
SysTick Calibration value
Read-only
0xE000E01C
STCALIB set through the Libero software