ARM Cortex-M0 User Manual

System Control
ARM DDI 0432C Copyright © 2009 ARM Limited. All rights reserved. 4-3
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4.2 System control register summary
Table 4-1 gives the system control registers. Each of these registers is 32 bits wide.
Note
• All system control registers are only accessible using word transfers. Any attempt
to read or write a halfword or byte is Unpredictable.
• If the processor is implemented without the SysTick timer, the SYST_CSR,
SYST_RVR, SYST_CVR, and SYST_CALIB register reads as zero, writes
ignored RAZ/WI.
• See the ARMv6-M ARM for more information about the system control registers,
and their addresses and access types, and reset values not shown in Table 4-1.
Table 4-1 System control registers
Name
Reset
value
Description
SYST_CSR - SysTick Control and Status Register in the ARMv6-M ARM
SYST_RVR Unknown SysTick Reload Value Register in the ARMv6-M ARM
SYST_CVR Unknown SysTick Current Value Register in the ARMv6-M ARM
SYST_CALIB
Implementation-defined
a
SysTick Calibration value Register in the ARMv6-M ARM
CPUID
0x410CC200 See CPUID Register on page 4-4
ICSR - Interrupt Control State Register in the ARMv6-M ARM
AIRCR
0x00000000
b
0x00008000
c
Application Interrupt and Reset Control Register in the ARMv6-M ARM
CCR - Configuration and Control Register in the ARMv6-M ARM
SHPR2 - System Handler Priority Register 2 in the ARMv6-M ARM
SHPR3 - System Handler Priority Register 3 in the ARMv6-M ARM
SHCSR - System Handler Control and State Register in the ARMv6-M ARM
a. This value is configured by the implementer during implementation. See the documentation supplied by your implementer
for more information.
b. Little-endian implementation.
c. Big-endian implementation.

ARM Cortex-M0 Specifications

General

Architecture	ARMv6-M
Data Bus Width	32-bit
Clock Speed	Up to 50 MHz
Interrupts	Nested Vectored Interrupt Controller (NVIC)
Number of Cores	1
Memory Protection	Optional Memory Protection Unit (MPU)
Interrupt Controller	Nested Vectored Interrupt Controller (NVIC)
Pipeline	3-stage
Max Clock Speed	50 MHz
Instruction Set	Thumb
Power Consumption	Low power design
Debug	Serial Wire Debug (SWD)
Die Size	Implementation dependent