SWRA466D February   2015  – August 2021 CC1310 , CC1310 , CC1352R , CC1352R , CC2538 , CC2538 , CC2620 , CC2620 , CC2630 , CC2630 , CC2640 , CC2640 , CC2640R2F , CC2640R2F , CC2640R2F-Q1 , CC2640R2F-Q1 , CC2642R , CC2642R , CC2642R-Q1 , CC2642R-Q1 , CC2650 , CC2650 , CC2650MODA , CC2650MODA , CC2652R , CC2652R , CC2652R7 , CC2652R7 , CC2652RB , CC2652RB , CC2652RSIP , CC2652RSIP

 

  1.   Trademarks
  2. 1Introduction
  3. 2ROM Bootloader
    1. 2.1 Configuring the Bootloader
      1. 2.1.1 CC2538
      2. 2.1.2 CC26x0
    2. 2.2 CC26x2
    3. 2.3 Communication Protocol
      1. 2.3.1 ACK/NACK
    4. 2.4 Interface Configuration
      1. 2.4.1 Hardware Pins
      2. 2.4.2 UART Configuration
      3. 2.4.3 Establishing Communication
      4. 2.4.4 Status Command
  4. 3Serial Bootloader Library (SBL)
    1. 3.1 SBL Return Values
    2. 3.2 SBL API
      1. 3.2.1 Device-Specific Functions
  5. 4Example Project
    1. 4.1 Hardware Setup
      1. 4.1.1 SmartRF06EB Virtual COM Port
        1. 4.1.1.1 External Serial Interface
      2. 4.1.2 LaunchPad Virtual COM Port
      3. 4.1.3 Bootloader Backdoor
    2. 4.2 Software Setup
      1. 4.2.1 Device Type
      2. 4.2.2 Baud Rate
    3. 4.3 Program Flow
      1. 4.3.1 Enumerate COM Ports
      2. 4.3.2 Create Device
      3. 4.3.3 Connect
      4. 4.3.4 Erase Flash Range
      5. 4.3.5 Write Flash Range
      6. 4.3.6 Calculate CRC32
      7. 4.3.7 Reset
  6. 5References
  7. 6Revision History

4.1.3 Bootloader Backdoor

The sblAppEx example is written for CC2538 and CC2650 (7x7) Evaluation Modules (EMs) and CC26x2 and CC2640R2 LaunchPads. The application image programmed onto the device triggers the SmartRF06EB or the LaunchPad to blink the LEDs. The firmware image enables the bootloader backdoor, so that the bootloader can be triggered using an IO pin.

The I/O pin used by the application image for opening the bootloader backdoor is shown in Table 4-1 and Table 4-2. This I/O pin is connected to the SmartRF06EB SELECT button. To enter the bootloader backdoor, hold down the SELECT button (corresponds to logic ‘0’) while you press the EM reset button on the SmartRF06EB. For the LaunchPad, the bootloader backdoor enable pin must be grounded when the LaunchPad reset button is pressed to enter the bootloader backdoor.

Table 4-1 Application Example IO Configuration: Evaluation Module Kits
SignalCC2538CC26x0EM Pin
QFN48/7x7QFN32/5x5QFN32/4x4
UART_RXPA0DIO2DIO1DIO11.07
UART_TXPA1DIO3DIO0DIO21.09
Bootloader backdoor enablePA3DIO11DIO9DIO71.14
Table 4-2 Application Example IO Configuration: LaunchPad
SignalCC2640R2 (1)CC26x2RCC1312RCC1352xLaunchPad Pin
UART_RXDIO2DIO2DIO2DIO123 (2)
UART_TXDIO3DIO3DIO3DIO134 (2)
Bootloader backdoor enableDIO11DIO11DIO11DIO1118
(1) The pinout is only valid for the QFN48/7x7 package.
(2) Reverse order for the CC2640R2 LaunchPad.