CHAPTER 1: System Overview
FM4 Peripheral Manual, Doc. No. 002-04856 Rev. *E 33
− SysTick Timer
SysTick Timer is a system timer for OS task management integrated into NVIC.
This family generates STCLK through dividing HCLK by eight and sets the values of SysTick
Calibration Value Register (Address: 0xE000E01C) as shown below:
bit31: NOREF = 0
bit30: SKEW = 1
bit23:0: TENMS = 0x0186A0 (100000)*1
*1: TENMS value is set to a value which becomes 10 ms when 1/8 clock of HCLK is input to STCLK and
that HCLK is in 80 MHz (10 MHz in 1/8 case).
The value of TENMS is not always 10 ms because HCLK can be changed to another frequency with
the clock control block. Therefore, it is required to calculate an appropriate interrupt timing according
to HCLK frequency.
FPU (Floating Point number processing Unit)
This family is equipped with a Cortex-M4 optional component FPU.
FPU has the following features:
− Conforms to IEEE754 Standard
− Single Precision Floating Point number processing Unit
− High Precision Fused MAC Calculation
DWT (Data Watchpoint & Trace Unit)
This family is equipped with DWT to use as the debug function.
DWT contains four comparators, and each comparator can be set as a hardware watchpoint.
ITM (Instrumentation Trace Macrocell)
This family is equipped with ITM as a debug function.
ITM is an optional application driven trace source that supports printf style debugging. The operation
system (OS) and application event are traced, and the system diagnostic information is sent.
FPB (Flash Patch & Breakpoint)
FPB has the following functions:
− Hardware Breakpoint function
− The function of remapping from Code memory space (FLASH memory) to SRAM space.
FPB is equipped with six instruction comparators and two literal comparators.
MPU (Memory Protection Unit)
This family is equipped with a Cortex-M4 optional component MPU, and maximum eight areas can be
defined.
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