1                  Microsoft's Azure RTOS ThreadX for Renesas RXv1
2
3                              Using the CC-RX Tools
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51.  Building the ThreadX run-time Library
6
7Please see the Samples repository on GitHub for the Azure RTOS demonstrations
8for the RXv1.
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10
112.  Demonstration System
12
13Please see the Samples repository on GitHub for the Azure RTOS demonstrations
14for the RXv1
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16
173.  System Initialization
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19The system entry point using Renesas tools is at the label _PowerON_Reset_PC.
20Use the resetprg.c file that comes with your release. Most notable is that Threadx
21applications run in supervisor mode and do not use user mode. Hence switching to
22user mode has been commented out.
23
24The vector area is set up using either intprg.c or in the file tx_initialize_low_level.src.
25The file tx_initialize_low_level.src is responsible for setting up various system data
26structures, interrupt vectors, and a periodic timer. This is the ideal place add
27application specific hardware initialization code.
28
29ThreadX utilizes CMT0 as a periodic timer interrupt source. The CMT0 interrupt is
30typically setup for 10ms periodic interrupts and the interrupt priority level is set to
31level 5 with the symbol CMT_RX_CFG_IPR in r_cmt_rx_config.h of Renesas CMT timer module
32(r_cmt_rx). You may change any of the timer parameters to suit your needs.
33
34In addition, _tx_initialize_low_level determines the first available address for use by
35the application, which is supplied as the sole input parameter to your application
36definition function, tx_application_define(). The mechanism is implemented by creating the
37FREEMEM section, this section should be linked last in the RAM area. tx_initialize_low_level
38will pick up the starting label of this section and put it in the global variable:
39_tx_initialize_unused_memory
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41
424.  Context Switch, Register Usage and Stack Frames
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44The RXv1 port for ThreadX uses the first software interrupt, SWINT, i.e., interrupt #27,
45to perform context switch with the interrupt priority level 1. This ISR is thus reserved
46when using ThreadX and the SWINT should not be manipulated in any way by the application.
47The port will setup the interrupt within _tx_initialize_low_level and the compiler will
48automatically install the necessary interrupt vector. As such no additional initialization
49is necessary by the application.
50
51The following defines the saved context stack frame used by the ThreadX port. The
52state of the CPU registers at the time of a context switch is saved on the running
53thread's stack The top of the suspended thread's stack is pointed to by
54tx_thread_stack_ptr in the associated thread control block TX_THREAD.
55
56    Offset        Interrupted Stack Frame
57
58     0x00                   ACC0
59     0x04                   R6
60     0x0C                   R7
61     0x10                   R8
62     0x14                   R9
63     0x18                   R10
64     0x1C                   R11
65     0x20                   R12
66     0x24                   R13
67     0x28                   R14
68     0x30                   R15
69     0x34                   R3
70     0x38                   R4
71     0x3C                   R5
72     0x40                   R1
73     0x44                   R2
74     0x48                   PC - return address
75     0x4C                   PSW
76
77Note: By default ccrx does not save the state of the accumulator register ACC0
78when entering an ISR. This means that if the ISR uses any of the DSP instructions the
79content of the register could be corrupted. Saving and restoring of the accumulator
80can be enabled by adding the -save_acc command line option.
81
82
835.  Improving Performance
84
85The distribution version of ThreadX is built without any compiler
86optimizations.  This makes it easy to debug because you can trace or set
87breakpoints inside of ThreadX itself.  Of course, this costs some
88performance.  To make ThreadX run faster, you can change the ThreadX Library
89project to disable debug information and enable the desired optimizations.
90
91In addition, you can eliminate the ThreadX basic API error checking by
92compiling your application code with the symbol TX_DISABLE_ERROR_CHECKING
93defined before tx_api.h is included.
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95
966. Timer Processing
97
98Timer processign is performed by calling __tx_timer_interrupt(). This should usually be done
99from within the callback of a periodic timer with a period of 100Hz. In the sample projects
100a Renesas Fit CMT periodic timer module (r_cmt_rx) is used as the timer source.
101
102
1037.  Interrupt Handling
104
105Interrupt handling is unaffected by the ThreadX port as such user interrupts can be
106written according to the toolchain's documentation. It is recommended not to use interrupt
107priority 1 as this is the priority of the context switch interrupt. However using interrupt
108priority 1 won't cause any negative side effects but doing so may slightly reduce
109performance. Please refer to the toolchain documentation for additional details on how to
110define interrupt service routines.
111
112
1138. Execution Profiling
114
115The RX port adds support for the Execution Profiling Kit (EPK). The EPK consists
116of the files tx_execution_profile.c and tx_execution_profile.h. See the documentation
117of the EPK for generic usage details.
118
119To add the EPK to your RXv1 release make the following modifications:
120
121* Enable the following define for both the Threadx library and the application
122TX_EXECUTION_PROFILE_ENABLE
123
124* Setup CMT1 as a free running 16 bit timer.
125
126* In tx_execution_profile.h, change following around line 52:
127
128#ifdef TX_EXECUTION_64BIT_TIME
129typedef unsigned long long              EXECUTION_TIME;
130#define TX_EXECUTION_MAX_TIME_SOURCE    0xFFFFFFFFFFFFFFFF
131#else
132typedef unsigned long                   EXECUTION_TIME;
133#define TX_EXECUTION_MAX_TIME_SOURCE    0xFFFF
134#endif
135
136/* Define basic constants for the execution profile kit.  */
137
138#define TX_EXECUTION_TIME_SOURCE         (EXECUTION_TIME)  *((USHORT *) 0x8800A)
139
140Rebuild the Threadx library and the application.
141Refer to the EPK documentation how to interpret the results.
142
143
1449.  Revision History
145
146For generic code revision information, please refer to the readme_threadx_generic.txt
147file, which is included in your distribution. The following details the revision
148information associated with this specific port of ThreadX:
149
150For generic code revision information, please refer to the readme_threadx_generic.txt
151file, which is included in your distribution. The following details the revision
152information associated with this specific port of ThreadX:
153
15404-25-2022  Release 6.1.11 changes:
155            tx_thread_schedule.src              Added low power support
156
15701-31-2022  Release 6.1.10 changes:
158            tx_port.h                           Removed system state macro, and added
159                                                missing interrupt control defines
160            tx_timer_interrupt.src              Added missing thread preemption logic
161
16210-15-2021  Release 6.1.9 changes:
163            tx_thread_context_restore.src       Removed unnecessary stack type placement
164            tx_thread_schedule.src              Removed unnecessary stack type checking
165            tx_thread_stack_build.src           Removed unnecessary stack type placement
166
16708-02-2021  Initial ThreadX release for the RXv1 using CC-RXX tools, version 6.1.8
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169
170Copyright(c) 1996-2022 Microsoft Corporation
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172
173https://azure.com/rtos
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176
177www.expresslogic.com