TI-RTOS overview
Nick Lethaby, TI-RTOS and IoT Ecosystem
May 2015
1
What is TI-RTOS?
Connectivity
Wi-Fi, Bluetooth®
Smart, ZigBee®,
Cellular (via PPP),
Wired TCP/IP,
TLS/SSL
Other
Middleware
USB, File
Systems
Power
Manager
T
I
R
T
O
S
User
Application
Tasks
APls
Real-time Kernel
Drivers
IoT MCU
Sensors
TI-RTOS development tools
• TI-RTOS works with the TI Code Composer Studio (CCS), IAR, and
GCC toolchains
• The RTOS Object Viewer enables developers to study the state of OS
objects such as tasks, stacks, and semaphores
– Available for CCS and IAR
• The RTOS Analyzer enables developers to look at execution history
including context switching and per-task CPU load
– Available for CCS
How TI-RTOS helps developers
• Provides pre-tested embedded software modules
– Connectivity protocols, power management, real-time kernel, …
– Eliminates need for these to be developed from scratch
– Enables developers to focus on their areas of application expertise
• No licensing hassles to use
– Completely free to use and deploy
• Reduced effort to port existing applications to new devices
– RTOS isolates application from hardware specifics
• Simpler development and maintenance of multi-function
applications
– Using multiple priorities and threads to integrate different functions
– Add new features without modifying real-time response
TI-RTOS kernel, drivers, & power manager
Connectivity
Wi-Fi, Bluetooth Smart,
ZigBee, Cellular (via
PPP), Wired TCP/IP,
TLS/SSL
Other
Middleware
USB, File
Systems
Power
Manager
T
I
R
T
O
S
User
Application
Tasks
APls
Real-time Kernel
Drivers
IoT MCU
Sensors
TI-RTOS kernel
• Designed for real-time applications
– Scheduler is deterministic so kernel system calls complete
operation in a predictable time
– Interrupt latency is low
– “Zero-latency Interrupts” enable kernel to be used in hard realtime applications
• Low footprint to meet MCU memory constraints
– Kernel is highly configurable so unneeded functions are
excluded
– Static configuration enables very low footprints by eliminating
need for heaps or create/delete calls if desired
• Tick suppression for enhanced low-power performance
Kernel services
IPC Services:
Events, Mailboxes,
Semaphores, Gates
Debug &
Analysis:
Logging,
diagnostics,
Hooks, stack
checking
Device-specific
services: Interrupt and
power management,
timers, exception
handling
Memory
Managers:
Heap, fixedsized buffers
Threading Services:
Tasks, Software Interrupts,
Clocks, Idle
An integrated approach to power management
Drivers & stacks:
• Request peripheral clocks and
power domains be enabled
• Set power-down constraints in
critical sections
Clock module:
• Provide next
scheduled
event
Power policy:
• Run in idle
task
• Select power
saving mode
Power manager:
• Manage clock gates & power domains
• Power-down and wake-up routines
• Power-down and wake-up latencies
• Record power-down constraints
Impact of TI-RTOS power manager
• TI MCU offers low power modes that consume exponentially less power
compared to simply sleeping the main Cortex-M core (WaitForInterrupt)
– The default power policy uses the latency data combined with its knowledge
of the next scheduled event to select the lowest possible power state, thus
greatly extending battery life
– Note: The data below is from the SimpleLink™ CC2640 wireless MCU
Power Mode
Wake-up Time
to CPU Active
Current Used
Active
NA
4.145 mA
WaitForInterrupt
A few cycles
1.4 µs
14 µs
2.028 mA
796 µA
1-2 µA
IDLE
STANDBY
TI-RTOS device drivers & board support
• Driver APIs are consistent across device families
– Makes applications easy to port to other device supported by TI-RTOS
• Drivers are designed for use with RTOS
– Thread-safe
– Block (on a semaphore) when waiting for I/O so CPU is released for another
thread to run
• Each supported board has a “board.c” file that contains the code for
initializing all the peripherals
• Drivers are “power-aware” for ultra low-power MCU devices
10
TI-RTOS device drivers
C28
C28+M3
TM4C
MSP432
Y
Y
Y
Y
Y
Y
Y
Y
Real-time clock
Timer
UART
Y
DMA-based UART
I2C
MSP430
CC3200
CC26xx
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
I2S
Y
Y
Y
SPI
Y
Y
Y
Y
Y
SPI-SD
Y
Y
Y
Y
Y
Y
Y
PWM
Y
Camera
Y
EMAC
Y
Y
USB
Y
Y
Watchdog
Y
Y
Y
Y
Y
Y
Y
TI-RTOS connectivity & middleware
Connectivity
Wi-Fi, Bluetooth®
Smart, ZigBee®,
Cellular (via PPP),
Wired TCP/IP,
TLS/SSL
Other
Middleware
USB, File
Systems
Power
Manager
T
I
R
T
O
S
User
Application
Tasks
APls
Real-time Kernel
Drivers
IoT MCU
Sensors
TI-RTOS: wireless connectivity
• TI-RTOS supports all on-chips stacks in TI SimpleLink™
wireless MCUs out-of-box
• TI-RTOS supports the SimpleLink™ Wi-Fi CC3100
wireless network processor out-of-box
Device
Wireless Stack
Comments
CC3200
Wi-Fi
CC3200 Wi-Fi host driver pre-tested on
TI-RTOS
CC2630
ZigBee
Stack runs by default on TI-RTOS
CC2640
Bluetooth Smart
Stack runs by default on TI-RTOS
MCU +
CC3100
Wi-Fi
TI-RTOS offers pre-integrated CC3100
host drivers using SPIs on MSP430,
MSP432 and TM4Cx
TI-RTOS TCP/IP stack
T
L
S
S
N
T
P
H
T
T
P
T
E
L
N
E
T
T
F
T
P
D
H
C
P
D
N
S
Standard BSD Sockets Interface
Route
Manager
IF
Manager
NAT
TCP
UDP
ICMP
IGMP
IP
PPP
ARP
Serial IF
Ethernet IF
Hardware Adaptation Layer
Ethernet Serial
Packet
Port
Driver
Driver
Timer
Driver
Hardware
User
LED
Driver
TCP/IP Key Features
 Supports both IPv4 and IPv6
 Standard BSD Sockets interface
 Zero-copy sockets interface available
 Highly configurable to meet footprint
constraints
 PPP/Serial Interface allows use with
third-party cellular modems
 SSL/TLS requires a licensing fee
USB stack
M
S
C
H
I
D
C
D
C
H
I
D
Class Driver
Application
Host
Device
Hardware Adaptation Layer
SD card, mouse,
UART, ….
Drivers
Hardware
DMA USB
Driver Driver
C
O
N
F
I
G
U
R
A
T
I
O
N
USB Key Features
 MSC Host Class Driver
 HID Host & Device Class Drivers
 CDC Device Class Driver
 Examples for each class driver
 Example of using MSC Host Driver
under FAT file system
File system
• TI uses an open source software called FatFs
• Key features:
– Both native and C RTS file APIs may be used
• C RTS APIs (fopen (), fread (), fwrite (), …) are plugged into file system
– Supports FAT12, FAT16, FAT32, and VFAT
• Long file names (VFAT) are not supported in the default build
• TI does NOT indemnify against VFAT patents
• Drivers options:
– SD Card (via SPI driver)
– USB flash drive (via USB MSC host)
Summary
• TI-RTOS enables developers to focus on their
specific areas of applications expertise by providing
pre-tested software building blocks:
– Multitasking kernel and device drivers
– Connectivity solutions: TCP/IP, Wi-Fi, BLE, and USB
– Advanced, easy-to-use power management
• Preemptive multitasking design paradigm simplifies
development and maintenance of embedded
applications
• TI-RTOS no-cost licensing removes commercial
barriers to deployment
For more information
• www.ti.com web page: www.ti.com/tool/ti-rtos
– Product brochure, white paper, manuals, software downloads
• e2e forum: http://e2e.ti.com/support/embedded/tirtos/
• Wiki: http://processors.wiki.ti.com/index.php/Main_Page
– Select ‘TI-RTOS’ category
• Download page:
– http://softwaredl.ti.com/dsps/dsps_public_sw/sdo_sb/targetcontent/tirtos/index.html
Product manager: Nick Lethaby (nlethaby@ti.com)