This document discusses RTOS and the Ameba board. It begins with an introduction to Ameba and its ARM Cortex-M3 processor. It then covers debugging the Ameba using DAP and CMSIS-DAP. The document discusses pros of Ameba and using it with Arduino. It goes on to discuss topics like why use an RTOS, environments like Arduino and Eclipse, microkernel design, memory management, scheduling, and inter-process communication. It concludes with discussions on future topics like power management, security, and benchmarks.

1. RTOS - AMEBA
Neo Jou

2. IOT 技術同好會
Search : Ameba / IoT

3. AMEBA

4. ARM ARCH

5. ARM

6. ARM CORTEX

7. AMEBA CPU
CPU 處理速度
cortem-M3
1.25 DMIPS/MHz
Ameba - 166MHz

8. DAP – DEBUG ACCESS
PORT
Ameba firmware download
UART/Serial to USB
JTAG/SWD debug
Ameba

9. CMSIS-DAP
USB mbed disk / USB-Serial / Debug

10. CMSIS-DAP SETUP
Usb 轉 serial
Driver : ARM mbed serial driver :
https://developer.mbed.org/handbook/Windows-serial-configuration
Usb disk – firmware CMSIS-DAP
DAP Link : https://github.com/mbedmicro/DAPLink
OpenOCD + CMSIS-DAP

11. AMEBA - PROS
相對於⼀般開發板
不⽤另外買 JTAG , 有 ARM CMSIS-DAP debug
有 wifi
Clock ⾼ , 速度快
省電

12. 空氣盒⼦

13. AMEBA

14. TOPICS
⼯商時間
RTOS
Why RTOS
Environment – Arduino / Eclipse – open source
Micro Kernel
memory
schedule
IPC
Future

15. WHY RTOS
Linux v.s. RTOS
Memory
Jitter / response time – audio
Real time
No-OS v.s. RTOS
擴充⽀援 / 多⼯

16. 即時 - REAL TIME
deadline : hard / soft
Linux : RTOS ?
kernel 非搶佔, user 權限⾼也無法搶佔
時間計算/限制機制
改良
重改 linux - PREEMPT_RT
dual kernel - 替換底層 - Xenomai ( 底層⽤ Nucleus )

17. 多⼯-1
真的需要多⼯?
* https://github.com/liuxuming/trochili

18. ARDUINO
setup()
loop()

19. 多⼯-2
ISR
* https://github.com/liuxuming/trochili

20. ARM MBED TICKER
https://developer.mbed.org/handbook/Ticker

21. TIMER CONS
HW timer 有限
SW timer : 延遲
No Preemptive / context switch ?
starvation

22. 多⼯ - 3
multi-tasks

23. 多⼯ - 3
⼯作 Task 程式執⾏最⼩單位?
Process =>Thread
Unix -> Mach
第⼀代 micro kernel
Mac OSX

24. THREAD

25. TOPICS
⼯商時間
RTOS
Why RTOS
Environment – arduino / eclipse
Micro Kernel
memory
schedule
IPC
Future

26. WHY ARDUINO
•
Prototype -> 量產 / ardupilot

27. ARDUINO
http://njiot.blogspot.tw/2016/03/arduino-ameba-100-rtos-1-5100.html
板⼦管理員

28. ARDUINO
http://njiot.blogspot.tw/2016/03/arduino-ameba-100-rtos-1-5100.html
板卡選擇

29. ARDUINO 設定檔
C:
Usersneo_jouAppDataLocalArduino15packagesn
jiothardwareameba1.2.1
Platform.txt
Gcc
Compiler / link options

30. ARDUINO

31. ECLIPSE + QEMU
http://njiot.blogspot.tw/2016/07/qemu-arm-gnu-arm-eclipse.html

32. TOPICS
⼯商時間
RTOS
Why RTOS
Environment – arduino / eclipse
Micro Kernel
memory
schedule
IPC
Future

33. 微核⼼
Memory
Thread
IPC

34. JIM HUANG / JSERV
Embedded system

35. RTOS
https://github.com/neojou/mini-arm-os/tree/master/07-Threads/Threads

36. TOPICS
⼯商時間
RTOS
Why RTOS
Environment – arduino / eclipse
Micro Kernel
memory
schedule
IPC
Future

37. TEXT / DATA
* Howard - HyperC OS
* Linker script -http://njiot.blogspot.tw/2016/03/arduino-ameba-100-textdatabssheapstack.html

38. MEMORY
C: malloc / free
sbrk()
linker script

39. MALLOC

40. RLX8195A
C:
Usersneo_jouAppDataLocalArduino15packagesnjiothardwareameba1.2.1variantsarduino
_amebalinker_scriptsgcc

41. TOPICS
⼯商時間
RTOS
Why RTOS
Environment – arduino / eclipse
Micro Kernel
memory
schedule
IPC
Future

42. REGISTERS

43. AAPCS
Procedure Call Standard for ARM Architecture

44. VECTOR TABLE

45. HANDLER
privileged
thread / handler
handler only have
privileged mode

46. AUTO PUSH / POP
Thread mode -> Handler mode

47. EXC_RETURN
Exception : thread ->
handler
LR : EXC_RETURN

48. ARDUINO SCHEDULER
和 mini-arm-os / RTX 很像
比 timer 優點 :
TCB : Task control block
各⾃有 stack

49. ARDUINO SCHEDULR
NUM_REGS=10, https://github.com/arduino-libraries/Scheduler/blob/master/src/Scheduler.cpp

50. SWITCH- SYSTICK

51. SWITCH - PENDSVC

52. TODO
Thread Priority
Scheduling
Round robin
…

53. 優先權錯逆
priority inversion
realtime - deadline

54. 優先權錯逆
⽕星探測計畫
http://wiki.csie.ncku.edu.tw/embedded/priority-inversion-on-Mars.pdf

55. TOPICS
⼯商時間
RTOS
Why RTOS
Environment – arduino / eclipse
Micro Kernel
memory
schedule
IPC
Future

56. IPC
Inter Process Communication
L4 kernel - 第⼆代微核⼼重點
f9-kernel: http://wiki.csie.ncku.edu.tw/
embedded/f9-kernel

57. L4
http://www.slideshare.net/microkerneldude/from-l3-to-sel4-what-have-we-learnt-in-20-years-l4
https://www.youtube.com/watch?v=RdoaFc5-1Rk

58. RTX ON AMEBA

59. RTX
Keil ARM
CMSIS API
IPC

60. CMSIS-RTOS
Cortex Microcontroller Software Interface Standard

61. SHARE MEMORY
No thread safe
flag
interrupt write status
thread polling

62. CRITICAL SECTION
atomic
spinlock / mutex / semaphore 差異?

63. IPC -⼩訊息傳遞
signal events
mutex
semaphore

64. IPC - ⼤訊息傳遞
message queue
mail queue

65. TOPICS
⼯商時間
RTOS
Why RTOS
Environment – arduino / eclipse
Micro Kernel
memory
schedule
IPC
Future

66. 複雜
drivers
wifi, usb, …
network protocol
TCP/IP
SSL / TLS
MQTT / HTTP
….

67. MBED OS
LoRa : https://docs.mbed.com/docs/lora-with-mbed/en/latest/intro-to-lora/

68. POWER
Tickless kernel
Busy waiting 耗電
WFI / WFE
中斷完成時直接休眠, 不回 Thread, 省下 stack push/pop
Systick or external sleep clock (32K)

69. ZEPHYR 和風
https://www.zephyrproject.org/doc/subsystems/power_management.html

70. 安全
資料安全
資訊隱藏與封裝 (C++)
資訊最⼩化公開原則
各⾃ stack
系統安全 : security boot
網路安全 : SSL/TLS

71. 安全- 硬體設計
Ameba Cortex-M3 :
MPU -> mbed uvisor
hardware crypto engine
加解密, 簽章 : AES / SHA-2
TrustZone : v8m : SAU
stack limit

72. FUTURE
Benchmark
ARM mbed / Arduino
CMSIS++ / mbed minar
NUTTX : ardupilot / cortex-m4
Zephyr : Linux ⼩弟
dynamic linking / module loading
hypervisor

73. THANK YOU
Q & A