Product Specs

Table Of Contents
7 CPU
Page
21
7
CPU
The ARM
®
Cortex
®
-M4 processor with floating-point unit (FPU) has a 32-bit instruction set (Thumb
®
-2
technology) that implements a superset of 16 and 32-bit instructions to maximize code density and
performance.
This processor implements several features that enable energy-efficient arithmetic and high-performance
signal processing including:
Digital signal processing (DSP) instructions
Single-cycle multiply and accumulate (MAC) instructions
Hardware divide
8 and 16-bit single instruction multiple data (SIMD) instructions
Single-precision floating-point unit (FPU)
The ARM Cortex Microcontroller Software Interface Standard (CMSIS) hardware abstraction layer for the
ARM Cortex processor series is implemented and available for the M4 CPU.
Real-time execution is highly deterministic in thread mode, to and from sleep modes, and when handling
events at configurable priority levels via the Nested Vectored Interrupt Controller (NVIC).
Executing code from flash will have a wait state penalty on the nRF52 Series. An instruction cache can be
enabled to minimize flash wait states when fetching instructions. For more information on cache, see Cache
on page 30. The section Electrical specification on page 21 shows CPU performance parameters
including wait states in different modes, CPU current and efficiency, and processing power and efficiency
based on the CoreMark
®
benchmark.
7.1 Floating point interrupt
The floating point unit (FPU) may generate exceptions when used due to e.g. overflow or underflow. These
exceptions will trigger the FPU interrupt (see Instantiation on page 24). To clear the IRQ line when an
exception has occurred, the relevant exception bit within the FPSCR register needs to be cleared. For more
information about the FPSCR or other FPU registers, see Cortex-M4 Devices Generic User Guide.
7.2 Electrical specification
7.2.1 CPU performance
The CPU clock speed is 64 MHz. Current and efficiency data is taken when in System ON and the CPU is
executing the CoreMark
benchmark. It includes power regulator and clock base currents. All other blocks
are IDLE.
Symbol
Description
Min.
Typ.
Max.
Units
W
FLASH
CPU wait states, running from flash, cache disabled
0
2
W
FLASHCACHE
CPU wait states, running from flash, cache enabled
0
3
W
RAM
CPU wait states, running from RAM
0
I
DDFLASHCACHE
CPU current, running from flash, cache enabled, LDO
7.4
mA
I
DDFLASHCACHEDCDC
CPU current, running from flash, cache enabled, DCDC 3V
3.7
mA
I
DDFLASH
CPU current, running from flash, cache disabled, LDO
8.0
mA
I
DDFLASHDCDC
CPU current, running from flash, cache disabled, DCDC 3V
3.9
mA
I
DDRAM
CPU current, running from RAM, LDO
6.7
mA
I
DDRAMDCDC
CPU current, running from RAM, DCDC 3V
3.3
mA
I
DDFLASH/MHz
CPU efficiency, running from flash, cache enabled, LDO
125
µA/
MHz
I
DDFLASHDCDC/MHz
CPU efficiency, running from flash, cache enabled, DCDC 3V
58
µA/
MHz