SPRS742L June   2011  – February 2021 F28M35E20B , F28M35H22C , F28M35H52C , F28M35H52C-Q1 , F28M35M22C , F28M35M52C

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1. 3.1 Functional Block Diagram
  4. 4 Revision History
  5. 5 Device Comparison
    1. 5.1 Related Products
  6. 6 Terminal Configuration and Functions
    1. 6.1 Pin Diagram
    2. 6.2 Signal Descriptions
      1. 6.2.1 Signal Descriptions
  7. 7 Specifications
    1. 7.1  Absolute Maximum Ratings
    2. 7.2  ESD Ratings – Automotive
    3. 7.3  ESD Ratings – Commercial
    4. 7.4  Recommended Operating Conditions
    5. 7.5  Power Consumption Summary
      1. 7.5.1 Current Consumption at 150-MHz C28x SYSCLKOUT and 75-MHz M3SSCLK
      2. 7.5.2 Current Consumption at 100-MHz C28x SYSCLKOUT and 100-MHz M3SSCLK
      3. 7.5.3 Current Consumption at 75-MHz C28x SYSCLKOUT and 75-MHz M3SSCLK
      4. 7.5.4 Current Consumption at 60-MHz C28x SYSCLKOUT and 60-MHz M3SSCLK
    6. 7.6  Electrical Characteristics
    7. 7.7  Thermal Resistance Characteristics for RFP PowerPAD Package
    8. 7.8  Thermal Design Considerations
    9. 7.9  Timing and Switching Characteristics
      1. 7.9.1 Power Sequencing
        1. 7.9.1.1 Reset ( XRS) Timing Requirements
        2. 7.9.1.2 Reset ( XRS) Switching Characteristics
        3. 7.9.1.3 Power Management and Supervisory Circuit Solutions
      2. 7.9.2 Clock Specifications
        1. 7.9.2.1 Changing the Frequency of the Main PLL
        2. 7.9.2.2 Input Clock Frequency and Timing Requirements, PLL Lock Times
          1. 7.9.2.2.1 Input Clock Frequency
          2. 7.9.2.2.2 Crystal Oscillator Electrical Characteristics
          3. 7.9.2.2.3 X1 Timing Requirements - PLL Enabled (1)
          4. 7.9.2.2.4 X1 Timing Requirements - PLL Disabled
          5. 7.9.2.2.5 XCLKIN Timing Requirements - PLL Enabled
          6. 7.9.2.2.6 XCLKIN Timing Requirements - PLL Disabled
          7. 7.9.2.2.7 PLL Lock Times
        3. 7.9.2.3 Output Clock Frequency and Switching Characteristics
          1. 7.9.2.3.1 Output Clock Frequency
          2. 7.9.2.3.2 XCLKOUT Switching Characteristics (PLL Bypassed or Enabled) (1) (1)
        4. 7.9.2.4 Internal Clock Frequencies
          1. 7.9.2.4.1 Internal Clock Frequencies (150-MHz Devices)
      3. 7.9.3 Timing Parameter Symbology
        1. 7.9.3.1 General Notes on Timing Parameters
        2. 7.9.3.2 Test Load Circuit
      4. 7.9.4 Flash Timing – Master Subsystem
        1. 7.9.4.1 Master Subsystem – Flash/OTP Endurance
        2. 7.9.4.2 Master Subsystem – Flash Parameters
        3. 7.9.4.3 Master Subsystem – Flash/OTP Access Timing
        4. 7.9.4.4 Master Subsystem – Flash Data Retention Duration
        5. 7.9.4.5 Master Subsystem – Minimum Required Flash/OTP Wait States at Different Frequencies
      5. 7.9.5 Flash Timing – Control Subsystem
        1. 7.9.5.1 Control Subsystem – Flash/OTP Endurance
        2. 7.9.5.2 Control Subsystem – Flash Parameters
        3. 7.9.5.3 Control Subsystem – Flash/OTP Access Timing
        4. 7.9.5.4 Control Subsystem – Flash Data Retention Duration
      6. 7.9.6 GPIO Electrical Data and Timing
        1. 7.9.6.1 GPIO - Output Timing
          1. 7.9.6.1.1 General-Purpose Output Switching Characteristics
        2. 7.9.6.2 GPIO - Input Timing
          1. 7.9.6.2.1 General-Purpose Input Timing Requirements
        3. 7.9.6.3 Sampling Window Width for Input Signals
        4. 7.9.6.4 Low-Power Mode Wakeup Timing
          1. 7.9.6.4.1 IDLE Mode Timing Requirements
          2. 7.9.6.4.2 IDLE Mode Switching Characteristics
          3. 7.9.6.4.3 IDLE Entry and Exit Timing Diagram
          4. 7.9.6.4.4 STANDBY Mode Timing Requirements
          5. 7.9.6.4.5 STANDBY Mode Switching Characteristics
          6. 7.9.6.4.6 STANDBY Entry and Exit Timing Diagram
          7. 7.9.6.4.7 HALT Mode Timing Requirements
          8. 7.9.6.4.8 HALT Mode Switching Characteristics
          9. 7.9.6.4.9 HALT Entry and Exit Timing Diagram
      7. 7.9.7 External Interrupt Electrical Data and Timing
        1. 7.9.7.1 External Interrupt Timing Requirements
        2. 7.9.7.2 External Interrupt Switching Characteristics
        3. 7.9.7.3 External Interrupt Timing Diagram
    10. 7.10 Analog and Shared Peripherals
      1. 7.10.1 Analog-to-Digital Converter
        1. 7.10.1.1 Sample Mode
        2. 7.10.1.2 Start-of-Conversion Triggers
        3. 7.10.1.3 Analog Inputs
        4. 7.10.1.4 ADC Result Registers and EOC Interrupts
        5. 7.10.1.5 ADC Electrical Data and Timing
          1. 7.10.1.5.1 ADC Electrical Characteristics
          2. 7.10.1.5.2 External ADC Start-of-Conversion Switching Characteristics
          3. 7.10.1.5.3 ADCSOCAO or ADCSOCBO Timing Diagram
      2. 7.10.2 Comparator + DAC Units
        1. 7.10.2.1 On-Chip Comparator and DAC Electrical Data and Timing
          1. 7.10.2.1.1 Electrical Characteristics of the Comparator/DAC
      3. 7.10.3 Interprocessor Communications
      4. 7.10.4 External Peripheral Interface
        1. 7.10.4.1 EPI General-Purpose Mode
        2. 7.10.4.2 EPI SDRAM Mode
        3. 7.10.4.3 EPI Host Bus Mode
          1. 7.10.4.3.1 EPI 8-Bit Host Bus (HB-8) Mode
            1. 7.10.4.3.1.1 HB-8 Muxed Address/Data Mode
            2. 7.10.4.3.1.2 HB-8 Non-Muxed Address/Data Mode
            3. 7.10.4.3.1.3 HB-8 FIFO Mode
          2. 7.10.4.3.2 EPI 16-Bit Host Bus (HB-16) Mode
            1. 7.10.4.3.2.1 HB-16 Muxed Address/Data Mode
            2. 7.10.4.3.2.2 HB-16 Non-Muxed Address/Data Mode
            3. 7.10.4.3.2.3 HB-16 FIFO Mode
        4. 7.10.4.4 EPI Electrical Data and Timing
          1. 7.10.4.4.1 EPI SDRAM Interface Switching Characteristics Over Recommended Operating Conditions (Unless Otherwise Noted) (see Figure 1-1 , Figure 1-1 , and Figure 1-1 )
          2. 7.10.4.4.2 EPI SDRAM Timing Diagrams
          3. 7.10.4.4.3 EPI Host-Bus 8 and Host-Bus 16 Interface Switching Characteristics Over Recommended Operating Conditions (Unless Otherwise Noted) (see Figure 1-1 , Figure 1-1 , Figure 1-1 , and Figure 1-1 )
          4. 7.10.4.4.4 EPI Host-Bus 8 and Host-Bus 16 Interface Timing Requirements (1) (see Figure 1-1 and Figure 1-1 )
          5. 7.10.4.4.5 EPI Host-Bus 8/16 Mode Timing Diagrams
          6. 7.10.4.4.6 EPI General-Purpose Interface Switching Characteristics Over Recommended Operating Conditions (Unless Otherwise Noted) (see Figure 1-1 )
          7. 7.10.4.4.7 EPI General-Purpose Interface Timing Requirements (see Figure 1-1 and Figure 1-1 )
          8. 7.10.4.4.8 EPI General-Purpose Interface Timing Diagrams
    11. 7.11 Master Subsystem Peripherals
      1. 7.11.1 Synchronous Serial Interface
        1. 7.11.1.1 Bit Rate Generation
        2. 7.11.1.2 Transmit FIFO
        3. 7.11.1.3 Receive FIFO
        4. 7.11.1.4 Interrupts
        5. 7.11.1.5 Frame Formats
      2. 7.11.2 Universal Asynchronous Receiver/Transmitter
        1. 7.11.2.1 Baud-Rate Generation
        2. 7.11.2.2 Transmit and Receive Logic
        3. 7.11.2.3 Data Transmission and Reception
        4. 7.11.2.4 Interrupts
      3. 7.11.3 Cortex-M3 Inter-Integrated Circuit
        1. 7.11.3.1 Functional Overview
        2. 7.11.3.2 Available Speed Modes
        3. 7.11.3.3 I2C Electrical Data and Timing
          1. 7.11.3.3.1 I2C Timing
      4. 7.11.4 Cortex-M3 Controller Area Network
        1. 7.11.4.1 Functional Overview
      5. 7.11.5 Cortex-M3 Universal Serial Bus Controller
        1. 7.11.5.1 Functional Description
      6. 7.11.6 Cortex-M3 Ethernet Media Access Controller
        1. 7.11.6.1 Functional Overview
        2. 7.11.6.2 MII Signals
        3. 7.11.6.3 EMAC Electrical Data and Timing
          1. 7.11.6.3.1 Timing Requirements for MIITXCK (see Figure 1-1 )
          2. 7.11.6.3.2 MIITXCK Timing Diagrams
          3. 7.11.6.3.3 Timing Requirements for MIIRXCK (see Figure 1-1 )
          4. 7.11.6.3.4 MIIRXCK Timing Diagram
          5. 7.11.6.3.5 Switching Characteristics Over Recommended Operating Conditions (Unless Otherwise Noted) for EMAC MII Transmit (see Figure 1-1 )
          6. 7.11.6.3.6 EMAC MII Transmit Timing Diagram
          7. 7.11.6.3.7 Timing Requirements for EMAC MII Receive (see Figure 1-1 )
          8. 7.11.6.3.8 EMAC MII Receive Timing Diagram
        4. 7.11.6.4 MDIO Electrical Data and Timing
          1. 7.11.6.4.1 Switching Characteristics Over Recommended Operating Conditions (Unless Otherwise Noted) for MDIO_CK (see Figure 1-1 )
          2. 7.11.6.4.2 MDIO_CK Timing Diagram
          3. 7.11.6.4.3 Switching Characteristics Over Recommended Operating Conditions (Unless Otherwise Noted) for MDIO as Output (see Figure 1-1 )
          4. 7.11.6.4.4 MDIO as Output Timing Diagram
          5. 7.11.6.4.5 Timing Requirements for MDIO as Input (see Figure 1-1 )
          6. 7.11.6.4.6 MDIO as Input Timing Diagram
    12. 7.12 Control Subsystem Peripherals
      1. 7.12.1 High-Resolution PWM and Enhanced PWM Modules
        1. 7.12.1.1 HRPWM Electrical Data and Timing
          1. 7.12.1.1.1 High-Resolution PWM Characteristics at SYSCLKOUT = (60–150 MHz)
        2. 7.12.1.2 ePWM Electrical Data and Timing
          1. 7.12.1.2.1 ePWM Timing Requirements
          2. 7.12.1.2.2 ePWM Switching Characteristics
          3. 7.12.1.2.3 Trip-Zone Input Timing
            1. 7.12.1.2.3.1 Trip-Zone Input Timing Requirements
      2. 7.12.2 Enhanced Capture Module
        1. 7.12.2.1 eCAP Electrical Data and Timing
          1. 7.12.2.1.1 eCAP Timing Requirement
          2. 7.12.2.1.2 eCAP Switching Characteristics
      3. 7.12.3 Enhanced Quadrature Encoder Pulse Module
        1. 7.12.3.1 eQEP Electrical Data and Timing
          1. 7.12.3.1.1 eQEP Timing Requirements
          2. 7.12.3.1.2 eQEP Switching Characteristics
      4. 7.12.4 C28x Inter-Integrated Circuit Module
        1. 7.12.4.1 Functional Overview
        2. 7.12.4.2 Clock Generation
        3. 7.12.4.3 I2C Electrical Data and Timing
          1. 7.12.4.3.1 I2C Timing
      5. 7.12.5 C28x Serial Communications Interface
        1. 7.12.5.1 Architecture
        2. 7.12.5.2 Multiprocessor and Asynchronous Communication Modes
      6. 7.12.6 C28x Serial Peripheral Interface
        1. 7.12.6.1 Functional Overview
        2. 7.12.6.2 SPI Electrical Data and Timing
          1. 7.12.6.2.1 Master Mode Timing
            1. 7.12.6.2.1.1 SPI Master Mode External Timing (Clock Phase = 0)
            2. 7.12.6.2.1.2 SPI Master Mode External Timing (Clock Phase = 1)
          2. 7.12.6.2.2 Slave Mode Timing
            1. 7.12.6.2.2.1 SPI Slave Mode External Timing (Clock Phase = 0)
            2. 7.12.6.2.2.2 SPI Slave Mode External Timing (Clock Phase = 1)
      7. 7.12.7 C28x Multichannel Buffered Serial Port
        1. 7.12.7.1 McBSP Electrical Data and Timing
          1. 7.12.7.1.1 McBSP Transmit and Receive Timing
            1. 7.12.7.1.1.1 McBSP Timing Requirements
            2. 7.12.7.1.1.2 McBSP Switching Characteristics
            3. 7.12.7.1.1.3 McBSP Timing Diagrams
          2. 7.12.7.1.2 McBSP as SPI Master or Slave Timing
            1. 7.12.7.1.2.1  McBSP as SPI Master or Slave Timing Requirements (CLKSTP = 10b, CLKXP = 0)
            2. 7.12.7.1.2.2  McBSP as SPI Master or Slave Switching Characteristics Over Recommended Operating Conditions (Unless Otherwise Noted) (CLKSTP = 10b, CLKXP = 0)
            3. 7.12.7.1.2.3  McBSP Timing as SPI Master or Slave: CLKSTP = 10b, CLKXP = 0 Timing Diagram
            4. 7.12.7.1.2.4  McBSP as SPI Master or Slave Timing Requirements (CLKSTP = 11b, CLKXP = 0)
            5. 7.12.7.1.2.5  McBSP as SPI Master or Slave Switching Characteristics Over Recommended Operating Conditions (Unless Otherwise Noted) (CLKSTP = 11b, CLKXP = 0)
            6. 7.12.7.1.2.6  McBSP Timing as SPI Master or Slave: CLKSTP = 11b, CLKXP = 0 Timing Diagram
            7. 7.12.7.1.2.7  McBSP as SPI Master or Slave Timing Requirements (CLKSTP = 10b, CLKXP = 1)
            8. 7.12.7.1.2.8  McBSP as SPI Master or Slave Switching Characteristics Over Recommended Operating Conditions (Unless Otherwise Noted) (CLKSTP = 10b, CLKXP = 1)
            9. 7.12.7.1.2.9  McBSP Timing as SPI Master or Slave: CLKSTP = 10b, CLKXP = 1 Timing Diagram
            10. 7.12.7.1.2.10 McBSP as SPI Master or Slave Timing Requirements (CLKSTP = 11b, CLKXP = 1)
            11. 7.12.7.1.2.11 McBSP as SPI Master or Slave Switching Characteristics Over Recommended Operating Conditions (Unless Otherwise Noted) (CLKSTP = 11b, CLKXP = 1)
            12. 7.12.7.1.2.12 McBSP Timing as SPI Master or Slave: CLKSTP = 11b, CLKXP = 1 Timing Diagram
  8. 8 Detailed Description
    1. 8.1  Memory Maps
      1. 8.1.1 Control Subsystem Memory Map
      2. 8.1.2 Master Subsystem Memory Map
    2. 8.2  Identification
    3. 8.3  Master Subsystem
      1. 8.3.1 Cortex-M3 CPU
      2. 8.3.2 Cortex-M3 DMA and NVIC
      3. 8.3.3 Cortex-M3 Interrupts
      4. 8.3.4 Cortex-M3 Vector Table
      5. 8.3.5 Cortex-M3 Local Peripherals
      6. 8.3.6 Cortex-M3 Local Memory
      7. 8.3.7 Cortex-M3 Accessing Shared Resources and Analog Peripherals
    4. 8.4  Control Subsystem
      1. 8.4.1 C28x CPU/FPU/VCU
      2. 8.4.2 C28x Core Hardware Built-In Self-Test
      3. 8.4.3 C28x Peripheral Interrupt Expansion
      4. 8.4.4 C28x Direct Memory Access
      5. 8.4.5 C28x Local Peripherals
      6. 8.4.6 C28x Local Memory
      7. 8.4.7 C28x Accessing Shared Resources and Analog Peripherals
    5. 8.5  Analog Subsystem
      1. 8.5.1 ADC1
      2. 8.5.2 ADC2
      3. 8.5.3 Analog Comparator + DAC
      4. 8.5.4 Analog Common Interface Bus
    6. 8.6  Master Subsystem NMIs
    7. 8.7  Control Subsystem NMIs
    8. 8.8  Resets
      1. 8.8.1 Cortex-M3 Resets
      2. 8.8.2 C28x Resets
      3. 8.8.3 Analog Subsystem and Shared Resources Resets
      4. 8.8.4 Device Boot Sequence
    9. 8.9  Internal Voltage Regulation and Power-On-Reset Functionality
      1. 8.9.1 Analog Subsystem: Internal 1.8-V VREG
      2. 8.9.2 Digital Subsystem: Internal 1.2-V VREG
      3. 8.9.3 Analog and Digital Subsystems: Power-On-Reset Functionality
      4. 8.9.4 Connecting ARS and XRS Pins
    10. 8.10 Input Clocks and PLLs
      1. 8.10.1 Internal Oscillator (Zero-Pin)
      2. 8.10.2 Crystal Oscillator/Resonator (Pins X1/X2 and VSSOSC)
      3. 8.10.3 External Oscillators (Pins X1 and XCLKIN)
      4. 8.10.4 Main PLL
      5. 8.10.5 USB PLL
    11. 8.11 Master Subsystem Clocking
      1. 8.11.1 Cortex-M3 Run Mode
      2. 8.11.2 Cortex-M3 Sleep Mode
      3. 8.11.3 Cortex-M3 Deep Sleep Mode
    12. 8.12 Control Subsystem Clocking
      1. 8.12.1 C28x Normal Mode
      2. 8.12.2 C28x IDLE Mode
      3. 8.12.3 C28x STANDBY Mode
    13. 8.13 Analog Subsystem Clocking
    14. 8.14 Shared Resources Clocking
    15. 8.15 Loss of Input Clock (NMI Watchdog Function)
    16. 8.16 GPIOs and Other Pins
      1. 8.16.1 GPIO_MUX1
      2. 8.16.2 GPIO_MUX2
      3. 8.16.3 AIO_MUX1
      4. 8.16.4 AIO_MUX2
    17. 8.17 Emulation/JTAG
    18. 8.18 Code Security Module
      1. 8.18.1 Functional Description
    19. 8.19 µCRC Module
      1. 8.19.1 Functional Description
      2. 8.19.2 CRC Polynomials
      3. 8.19.3 CRC Calculation Procedure
      4. 8.19.4 CRC Calculation for Data Stored In Secure Memory
  9. 9 Applications, Implementation, and Layout
    1. 9.1 TI Reference Design
  10. 10Device and Documentation Support
    1. 10.1 Device and Development Support Tool Nomenclature
    2. 10.2 Tools and Software
    3. 10.3 Documentation Support
    4. 10.4 Trademarks
    5. 10.5 Support Resources
    6. 10.6 Electrostatic Discharge Caution
    7. 10.7 Glossary
  11. 11Mechanical, Packaging, and Orderable Information
    1. 11.1 Packaging Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.8.4 Device Boot Sequence

The boot sequence of Concerto is used to configure the Master Subsystem and the Control Subsystem for execution of application code. The boot sequence involves both internal resources, and resources external to the device. These resources include: Master Subsystem Bootloader code (M-Bootloader) factory-programmed inside the Master Subsystem Boot ROM (M-Boot ROM); Control Subsystem Bootloader code (C-Bootloader) factory-programmed inside the Control Subsystem Boot ROM (C-Boot ROM); four GPIO_MUX pins for Master boot mode selection; internal Flash and RAM memories; and selected Cortex-M3 and C28x peripherals for loading the application code into the Master and Control Subsystems.

The boot sequence starts when the Master Subsystem comes out of reset, which can be caused by device power up, external reset, debugger reset, software reset, Cortex-M3 watchdog reset, or Cortex-M3 NMI watchdog reset. While the M-Bootloader starts executing first, the C-Bootloader starts soon after, and then both bootloaders work in tandem to configure the device, load application code for both processors (if not already in the Flash), and branch the execution of each processor to a selected location in the application code.

Execution of the M-Bootloader commences when an internal reset signal goes from active to inactive state. At that time, the Control Subsystem and the Analog Subsystem continue to be in reset state until the Master Subsystem takes them out of reset. The M-Bootloader first initializes some device-level functions, then the M-Bootloader initializes the Master Subsystem. Next, the M-Bootloader takes the Control Subsystem and the Analog Subsystem/ACIB out of reset. When the Control Subsystem comes out of reset, its own C-Bootloader starts executing in parallel with the M-Bootloader. After initializing the Control Subsystem, the C-Bootloader enters the C28x processor into the IDLE mode (to wait for the M-Bootloader to wake up the C28x processor later through the MTOCIPC1 interrupt). Next, the M-Bootloader reads four GPIO pins (see Table 8-17) to determine the boot mode for the rest of the M-Bootloader operation.

Table 8-17 Master Subsystem Boot Mode Selection
BOOT MODE NO.(1) MASTER SUBSYSTEM BOOT MODES PF2_GPIO34
(Bmode_pin4)(2)(3)		 PF3_GPIO35
(Bmode_pin3)(2)		 PG7_GPIO47
(Bmode_pin2)(2)		 PG3_GPIO43
(Bmode_pin1)(2)
0 Boot from Parallel GPIO 0 0 0 0
1 Boot to Master Subsystem RAM 0 0 0 1
2 Boot from Master Subsystem serial peripherals (UART0/SSI0/I2C0) 0 0 1 0
3 Boot from Master Subsystem CAN interface 0 0 1 1
4 Boot from Master Subsystem Ethernet interface 0 1 0 0
5 Not supported (Defaults to Boot-to-Flash) 0 1 0 1
6(5) Boot-to-OTP 0 1 1 0
7 Boot to Master Subsystem Flash memory 0 1 1 1
8(4) Not supported (Defaults to Boot-to-Flash) 1 0 0 0
9(4) Boot from Master Subsystem serial peripheral –
SSI0 Master		 1 0 0 1
10(4) Boot from Master Subsystem serial peripheral –
I2C0 Master		 1 0 1 0
11(4) Not supported (Defaults to Boot-to-Flash) 1 0 1 1
12(4) Not supported (Defaults to Boot-to-Flash) 1 1 0 0
13(4) Not supported (Defaults to Boot-to-Flash) 1 1 0 1
14(4) Not supported (Defaults to Boot-to-Flash) 1 1 1 0
15(4) Not supported (Defaults to Boot-to-Flash) 1 1 1 1
(1) Silicon revision A allows the user to change the GPIO pins used to determine the boot mode. Silicon revision 0 does not have this option. See the Concerto F28M35x Technical Reference Manual for additional information.
(2) By default, GPIO terminals are not pulled up (they are floating).
(3) On silicon revision 0, PF2_GPIO34 is a "don't care". So, the state of PF2_GPIO34 should not affect boot mode selection.
(4) Boot Modes 8–15 are not supported on silicon revision 0.
(5) Supported only in TMS version. On all other versions, this mode defaults to Boot-to-Flash.

Boot Mode 7 and Boot Mode 15 cause the Master program to branch execution to the application in the Master Flash memory. This branching requires that the Master Flash be already programmed with valid code; otherwise, a hard fault exception is generated and the Cortex-M3 goes back to the above reset sequence. (Therefore, for a factory-fresh device, the M-Bootloader will be in a continuous reset loop until the JTAG debug probe is connected and a debug session started.) If the Master Subsystem Flash has already been programmed, the application code will start execution. Typically, the Master Subsystem application code will then establish data communication with the C28x [through the IPC (Interprocessor Communications peripheral)] to coordinate the rest of the boot process with the Control Subsystem. Following reset, the internal pullup resistors on GPIOs are disabled. Therefore, Boot Mode 15, for example, will typically require four external pullups.

Boot Mode 1 causes the Master boot program to branch to Cortex-M3 RAM, where the Cortex-M3 processor starts executing code that has been preloaded earlier. Typically, this mode is used during development of application code meant for Flash, but which has to be first tested running out of RAM. In this case, the user would typically load the application code into RAM using the debugger, and then issue a debugger reset, while setting the four boot pins to 0001b. From that point on, the rest of the boot process on the Master Subsystem side is controlled by the application code.

Boot Modes 0, 2, 3, 4, 9, 10, and 12 are used to load the Master application code from an external peripheral before branching to the application code. This process is different from the process in Boot Modes 1, 7, and 15, where the application code was either already programmed in Flash or loaded into RAM by the JTAG debug probe. If the boot mode selection pins are set to 0000b, the M-Bootloader (running out of M-Boot ROM) will start uploading the Master application code from preselected Parallel GPIO_MUX pins. If the boot pins are set to 0010b, the application code will be loaded from the Master Subsystem UART0, SSI0, or I2C0 peripheral. (SSI0 and I2C0 are configured to work in Slave mode in this Boot Mode.) If the boot pins are set to 0011b, the application code will be loaded from the Master Subsystem CAN interface. Furthermore, if the boot pins are set to 0100b, the application code will be loaded through the Master Subsystem Ethernet interface; the IOs used in this Boot Mode are compatible with the F28M35x device. If the boot pins are set to 1001b or 1010b, then the application code will be loaded through the SSI0 or I2C0 interface, respectively. SSI0 and I2C0 loaders work in Master Mode in this boot mode.

Regardless of the type of boot mode selected, once the Master application code is resident in Master Flash or RAM, the next step for the M-Bootloader is to branch to Master Flash or RAM. At that point, the application code takes over control from the M-Bootloader, and the boot process continues as prescribed by the application code. At this stage, the Master application program typically establishes communication with the C-Bootloader, which by now, would have already initialized the Control Subsystem and forced the C28x to go into IDLE mode. To wake the Control Subsystem out of IDLE mode, the Master application issues the Master-to-Control-IPC-interrupt 1 (MTOCIPCINT1). Once the data communication has been established through the IPC, the boot process can now also continue on the Control Subsystem side.

The rest of the Control Subsystem boot process is controlled by the Master Subsystem application issuing IPC instructions to the Control Subsystem, with the C-Bootloader interpreting the IPC commands and acting on them to continue the boot process. At this stage, a boot mode for the Control Subsystem can be established. The Control Subsystem boot modes are similar to the Master Subsystem boot modes, except for the mechanism by which they are selected. The Control Subsystem boot modes are chosen through the IPC commands from the Master application code to the C-Bootloader, which interprets them and acts accordingly. The choices are, as above, to branch to already existing Control application code in Flash, to branch to preloaded code in RAM (development mode), or to upload the Control application code from one of several available peripherals (see Table 8-18). As before, once the Control application code is in place (in Flash or RAM), the C-Bootloader branches to Flash or RAM, and from that point on, the application code takes over.

Table 8-18 Control Subsystem Boot Mode Selection
CONTROL SUBSYSTEM
BOOT MODES		 MTOCIPCBOOTMODE
REGISTER VALUE		 DESCRIPTION
BOOT_FROM_RAM 0x0000 0001 Upon receiving this command from the Master Subsystem, C-Boot ROM will branch to the Control Subsystem RAM entry point location and start executing code from there.
BOOT_FROM_FLASH 0x0000 0002 Upon receiving this command, C-Boot ROM will branch to the Control Subsystem FLASH entry point and start executing code from there.
BOOT_FROM_SCI 0x0000 0003 Upon receiving this command, C-Boot ROM will boot from the Control Subsystem SCI peripheral.
BOOT_FROM_SPI 0x0000 0004 Upon receiving this command, C-Boot ROM will boot from the Control Subsystem SPI interface.
BOOT_FROM_I2C 0x0000 0005 Upon receiving this command, C-Boot ROM will boot from the Control Subsystem I2C interface.
BOOT_FROM_PARALLEL 0x0000 0006 Upon receiving this command, C-Boot ROM will boot from the Control Subsystem GPIO.

The boot process can be considered completed once the Cortex-M3 and C28x are both running out of their respective application programs. Following the boot sequence, the C-Bootloader is still available to interpret and act upon an assortment of IPC commands that can be issued from the Master Subsystem to perform a variety of configuration, housekeeping, and other functions. See the Concerto F28M35x Technical Reference Manual for additional information on Concerto boot modes, IPC commands, and the underlying boot philosophy.