readme_threadx.txt
1 Microsoft's Azure RTOS ThreadX for Cortex-M55
2
3 Using the AC6 Tools in Keil uVision
4
51. Import the ThreadX Projects
6
7In order to build the ThreadX library and the ThreadX demonstration, first open
8the AzureRTOS.uvmpw workspace (located in the "example_build" directory)
9into Keil.
10
11
122. Building the ThreadX run-time Library
13
14Building the ThreadX library is easy; simply set the ThreadX_Library project
15as active, then then build the library. You should now observe the compilation
16and assembly of the ThreadX library. This project build produces the ThreadX
17library file ThreadX_Library.lib.
18Files tx_thread_stack_error_handler.c and tx_thread_stack_error_notify.c
19replace the common files of the same name.
20
213. Demonstration System
22
23The ThreadX demonstration is designed to execute under the Keil debugger on the
24FVP_MPS2_Cortex-M55_MDK simulator.
25
26Building the demonstration is easy; simply select the "Batch Build" button.
27You should now observe the compilation and assembly of the ThreadX demonstration of
28both the demo_secure_zone and demo_threadx_non-secure_zone projects.
29Then click the Start/Stop Debug Session button to start the simulator and begin debugging.
30You are now ready to execute the ThreadX demonstration.
31
32
334. System Initialization
34
35The entry point in ThreadX for the Cortex-M55 using AC6 tools uses the standard AC6
36Cortex-M55 reset sequence. From the reset vector the C runtime will be initialized.
37
38The ThreadX tx_initialize_low_level.s file is responsible for setting up
39various system data structures, the vector area, and a periodic timer interrupt
40source.
41
42In addition, _tx_initialize_low_level determines the first available
43address for use by the application, which is supplied as the sole input
44parameter to your application definition function, tx_application_define.
45
46
475. Register Usage and Stack Frames
48
49The following defines the saved context stack frames for context switches
50that occur as a result of interrupt handling or from thread-level API calls.
51All suspended threads have the same stack frame in the Cortex-M55 version of
52ThreadX. The top of the suspended thread's stack is pointed to by
53tx_thread_stack_ptr in the associated thread control block TX_THREAD.
54
55Non-FPU Stack Frame:
56
57 Stack Offset Stack Contents
58
59 0x00 LR Interrupted LR (LR at time of PENDSV)
60 0x04 r4 Software stacked GP registers
61 0x08 r5
62 0x0C r6
63 0x10 r7
64 0x14 r8
65 0x18 r9
66 0x1C r10
67 0x20 r11
68 0x24 r0 Hardware stacked registers
69 0x28 r1
70 0x2C r2
71 0x30 r3
72 0x34 r12
73 0x38 lr
74 0x3C pc
75 0x40 xPSR
76
77FPU Stack Frame (only interrupted thread with FPU enabled):
78
79 Stack Offset Stack Contents
80
81 0x00 LR Interrupted LR (LR at time of PENDSV)
82 0x04 s16 Software stacked FPU registers
83 0x08 s17
84 0x0C s18
85 0x10 s19
86 0x14 s20
87 0x18 s21
88 0x1C s22
89 0x20 s23
90 0x24 s24
91 0x28 s25
92 0x2C s26
93 0x30 s27
94 0x34 s28
95 0x38 s29
96 0x3C s30
97 0x40 s31
98 0x44 r4 Software stacked registers
99 0x48 r5
100 0x4C r6
101 0x50 r7
102 0x54 r8
103 0x58 r9
104 0x5C r10
105 0x60 r11
106 0x64 r0 Hardware stacked registers
107 0x68 r1
108 0x6C r2
109 0x70 r3
110 0x74 r12
111 0x78 lr
112 0x7C pc
113 0x80 xPSR
114 0x84 s0 Hardware stacked FPU registers
115 0x88 s1
116 0x8C s2
117 0x90 s3
118 0x94 s4
119 0x98 s5
120 0x9C s6
121 0xA0 s7
122 0xA4 s8
123 0xA8 s9
124 0xAC s10
125 0xB0 s11
126 0xB4 s12
127 0xB8 s13
128 0xBC s14
129 0xC0 s15
130 0xC4 fpscr
131
132
1336. Improving Performance
134
135To make ThreadX and the application(s) run faster, you can enable
136all compiler optimizations.
137
138In addition, you can eliminate the ThreadX basic API error checking by
139compiling your application code with the symbol TX_DISABLE_ERROR_CHECKING
140defined.
141
142
1437. Interrupt Handling
144
145ThreadX provides complete and high-performance interrupt handling for Cortex-M55
146targets. There are a certain set of requirements that are defined in the
147following sub-sections:
148
149
1507.1 Vector Area
151
152The Cortex-M55 vectors start at the label __Vectors or similar. The application may modify
153the vector area according to its needs. There is code in tx_initialize_low_level() that will
154configure the vector base register.
155
156
1577.2 Managed Interrupts
158
159ISRs can be written completely in C (or assembly language) without any calls to
160_tx_thread_context_save or _tx_thread_context_restore. These ISRs are allowed access to the
161ThreadX API that is available to ISRs.
162
163ISRs written in C will take the form (where "your_C_isr" is an entry in the vector table):
164
165void your_C_isr(void)
166{
167
168 /* ISR processing goes here, including any needed function calls. */
169}
170
171ISRs written in assembly language will take the form:
172
173
174 .global your_assembly_isr
175 .thumb_func
176your_assembly_isr:
177; VOID your_assembly_isr(VOID)
178; {
179 PUSH {r0, lr}
180;
181; /* Do interrupt handler work here */
182; /* BL <your interrupt routine in C> */
183
184 POP {r0, lr}
185 BX lr
186; }
187
188Note: the Cortex-M55 requires exception handlers to be thumb labels, this implies bit 0 set.
189To accomplish this, the declaration of the label has to be preceded by the assembler directive
190.thumb_func to instruct the linker to create thumb labels. The label __tx_IntHandler needs to
191be inserted in the correct location in the interrupt vector table. This table is typically
192located in either your runtime startup file or in the tx_initialize_low_level.s file.
193
194
1958. FPU Support
196
197ThreadX for Cortex-M55 supports automatic ("lazy") VFP support, which means that applications threads
198can simply use the VFP and ThreadX automatically maintains the VFP registers as part of the thread
199context.
200
201
2029. Revision History
203
204For generic code revision information, please refer to the readme_threadx_generic.txt
205file, which is included in your distribution. The following details the revision
206information associated with this specific port of ThreadX:
207
20806-02-2021 Release 6.1.7 changes:
209 tx_port.h Remove unneeded include file
210 tx_thread_secure_stack_initialize.S New file
211 tx_thread_schedule.S Added secure stack initialize to SVC hander
212 tx_thread_secure_stack.c Fixed stack pointer save, initialize in handler mode
213
21404-02-2021 Release 6.1.6 changes:
215 tx_port.h Updated macro definition
216 tx_thread_schedule.s Added low power support
217
21803-02-2021 The following files were changed/added for version 6.1.5:
219 tx_port.h Added ULONG64_DEFINED
220
22109-30-2020 Initial ThreadX 6.1 version for Cortex-M55 using AC6 tools.
222
223
224Copyright(c) 1996-2020 Microsoft Corporation
225
226
227https://azure.com/rtos
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229
