First Day
Introduction to ARMv8-M Architecture
- ARM Cortex-M33 processor macrocell
- ARMv8-M Programmer’s model
- Instruction pipeline
- Fixed memory map
- Privilege, modes and stacks
- Memory Protection Unit
- Security extensions
- Interrupt handling
- Nested Vectored Interrupt Controller [NVIC]
- Power management
- Debug
ARM Cortex-M33 core
- Special purpose registers
- Datapath and pipeline
- Write buffer
- Bit-banding
- System timer
- State, privilege and stacks
- System control block
Architecture of a SoC based on Cortex-M33
- Internal bus matrix
- External bus matrix to support DMA masters
- Connecting peripherals
- Sharing resources between Cortex-M4 and other CPUs
- Connection to Power Manager Controller
Second day
Embedded Software Development with Cortex-M33
- Application startup
- Placing code, data, stack and heap in the memory map, scatterloading
- Reset and initialisation
- Placing a minimal vector table
- Further memory map considerations, 8-byte stack alignment in handlers
| Exercise: |
Create a standalone C application displaying data on a serial line |
The T32 Instruction Set variant supported on ARMv8M
- General points on syntax
- Data processing instructions
- Branch and control flow instructions
- Memory access instructions
- Exception generating instructions
- If…then conditional blocks
- Stack in operation
- Stack limit registers
- Exclusive load and store instructions, implementing atomic sequences
- Memory barriers and synchronization
| Exercise: |
Create assembly-level functions to implement simple algorithms |
Synchronization and Semaphores
- Exclusive access instructions
- The Local, Global and External monitors
- Interaction with exclusive access instructions
- Load Exclusive and Store Exclusive usage and constraints
| Exercise: |
Implement atomic variable manipulation using exclusive access instructions |
| Exercise: |
Implement spinlocks |
Cortex-M DSP Instruction Set
- Multiply instructions
- Packing / unpacking instructions
- V6 ARM SIMD packed add / sub instructions
- SIMD combined add/sub instructions, implementing canonical complex operations
- Multiply and multiply accumulate instructions
- SIMD sum absolute difference instructions
- SIMD select instruction
- Saturation instructions
| Exercise: |
Code assembly-language optimized data-processing algorithms |
Third day
CMSIS DSP support
- The CMSIS library framework
- The CMSIS DSP intrinsic functions
- The optimized CMSIS data-processing functions
| Exercise: |
Recode data-processing functions in C using intrinsics |
| Exercise: |
Recode the same using CMSIS high-level data processing functions |
| Exercise: |
Compare performance of the various implementations |
Floating point Unit
- Introduction to IEEE754
- Floating point arithmetic
- Cortex-M4F single precision FPU
- Register bank
- Enabling the FPU
- FPU performance, fused MAC
- Improving the performance by selection flush-to-zero mode and default NaN mode
- Extension of AAPCS to include FP registers
| Exercise: |
Enable the FPU and use it for simple floating point algorithms |
C/C++ Compiler hints and Tips for Cortex-M33
- Mixing C/C++ and assembly
- Coding with GCC compiler
- Measuring stack usage
- Unaligned accesses
- Local and global data issues, alignment of structures
- Further optimisations, linker feedback
| Exercise: |
Measure stack usage of a program |
| Exercise: |
Place a user-defined data structure at a fixed address |
Exceptions
- Exception behavior, exception return
- Non-maskable exceptions
- Privilege, modes and stacks
- Fault escalation
- Priority boosting
- Vector table
| Exercise: |
Manage synchronous exceptions to simplify FPU usage |
| Exercise: |
Manage the SVC exception to switch between user and privileged modes |
Fourth day
Interrupts
- Basic interrupt operation, micro-coded interrupt mechanism
- Interrupt entry / exit, timing diagrams
- Interrupt stack
- Tail chaining
- Interrupt response, pre-emption
- Interrupt prioritization
- Interrupt handlers
- The Nested Vectored Interrupt Controller (NVIC)
| Exercise: |
Handle a timer interrupt in C or assembly language |
| Exercise: |
Manage interrupt masking and nesting between two interrupts |
The Security Extension
- Security states
- Register banking between security states
- Stacks and security states
- Security Extension and exceptions
- Secure state address protection
- Secure and Non-Secure states interactions
- Secure sate transitions
- Function calls from Non-Secure to Secure state
- Returning from Secure state
- Exceptions and the Security Extension
- Handling Secure Exceptions
- Handling Non-Secure Exceptions while in the Secure state
- Returning from a Non-Secure exception to the Secure state
- The Security Attribution Unit
- The Implementation Defined Attribution Unit
| Exercise: |
Implement a minimal secure monitor |
Memory Protection Unit
- Memory types
- Access order
- Memory barriers, self-modifying code
- Memory protection overview, ARM v8 PMSA
- Cortex-M33 MPU and bus faults
- Fault status and address registers
- Region overview, memory type and access control
- Setting up the MPU
| Exercise: |
Use the MPU to protect an area of memory against unintended access |
Debugging features
- Invasive Debug
- Coresight debug infrastructure
- Halt mode
- Vector catching
- Debug event sources
- Flash patch and breakpoint features
- Data watchpoint and trace
- ARM debug interface specification
- Coresight components
- AHB-Access Port
- Possible DP implementations: Serial Wire JTAG Debug Port [SWJ-DP] or SW-DP
- Non-Invasive debug
- Basic ETM operation
- Instruction trace principles
- Instrumentation trace macrocell
- ITM stimulus port registers
- DWT trace packets
- Hardware event types
- Instruction tracing
- Synchronization packets
- Interface between on-chip trace data from ETM and Instrumentation Trace Macrocell [ITM]
- TPIU components
- Serial Wire connection
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