А System Control Block -- это вот что:
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Cortex-M3 Peripherals > System control block4.3. System control block
The System control block (SCB) provides system implementation information, and system control. This includes configuration, control, and reporting of the system exceptions. The system control block registers are:
Table 4.12. Summary of the system control block registers
Address Name Type Required privilege Reset value Description
0xE000E008 ACTLR RW Privileged 0x00000000 Auxiliary Control Register
0xE000ED00 CPUID RO Privileged 0x412FC230 CPUID Base Register
0xE000ED04 ICSR RW Privileged 0x00000000 Interrupt Control and State Register
0xE000ED08 VTOR RW Privileged 0x00000000 Vector Table Offset Register
0xE000ED0C AIRCR RW Privileged 0xFA050000 Application Interrupt and Reset Control Register
0xE000ED10 SCR RW Privileged 0x00000000 System Control Register
0xE000ED14 CCR RW Privileged 0x00000200 Configuration and Control Register
0xE000ED18 SHPR1 RW Privileged 0x00000000 System Handler Priority Register 1
0xE000ED1C SHPR2 RW Privileged 0x00000000 System Handler Priority Register 2
0xE000ED20 SHPR3 RW Privileged 0x00000000 System Handler Priority Register 3
0xE000ED24 SHCRS RW Privileged 0x00000000 System Handler Control and State Register
0xE000ED28 CFSR RW Privileged 0x00000000 Configurable Fault Status Register
0xE000ED28 MMSR[b] RW Privileged 0x00 MemManage Fault Status Register
0xE000ED29 BFSR [b] RW Privileged 0x00 BusFault Status Register
0xE000ED2A UFSR [b] RW Privileged 0x0000 UsageFault Status Register
0xE000ED2C HFSR RW Privileged 0x00000000 HardFault Status Register
0xE000ED34 MMAR RW Privileged Unknown MemManage Fault Address Register
0xE000ED38 BFAR RW Privileged Unknown BusFault Address Register
0xE000ED3C AFSR RW Privileged 0x00000000 Auxiliary Fault Status Register
[a] See the register description for more information.
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[b] A subregister of the CFSR.
Без использования некоторых из этих регистров порой никак. Например, для входа в режимы энергосбережения не обойтись без обращения к регистру SCR.