SWRA667 January   2020 CC1312PSIP , CC1312R , CC1314R10 , CC1352P , CC1352P7 , CC1352R , CC1354P10 , CC1354R10 , CC2642R , CC2642R-Q1 , CC2652P , CC2652R , CC2652R7 , CC2652RB , CC2652RSIP

 

  1.   Cryptographic Performance and Energy Efficiency on SimpleLink™ CC13x2/CC26x2 Wireless MCUs
    1.     Trademarks
    2. 1 Abbreviations and Acronyms
    3. 2 Introduction
    4. 3 Benefits of Cryptographic Acceleration in Embedded Security Solutions
    5. 4 TI Drivers for SimpleLink MCUs
      1. 4.1 Power Management Overview
      2. 4.2 Return Behavior
        1. 4.2.1 Runtime Overhead
      3. 4.3 Efficient Power Management
    6. 5 CC13x2/CC26x2 Crypto Peripherals
      1. 5.1 AES and Hash Crypto Accelerator
      2. 5.2 Public Key Accelerator
        1. 5.2.1 ECDH Power Management Driver Example
      3. 5.3 TRNG
    7. 6 Benchmarks
      1. 6.1 AES and Hash Crypto Accelerator Based Drivers
        1. 6.1.1 AES CBC
        2. 6.1.2 AES CCM
        3. 6.1.3 AES GCM
        4. 6.1.4 AES CTR DRBG
        5. 6.1.5 SHA-224
        6. 6.1.6 SHA-256
        7. 6.1.7 SHA-384
        8. 6.1.8 SHA-512
      2. 6.2 PKA Engine Based Drivers
        1. 6.2.1 ECDH
        2. 6.2.2 ECDSA
        3. 6.2.3 ECJPAKE
      3. 6.3 TRNG Based Drivers
        1. 6.3.1 TRNG
    8. 7 Conclusion
    9. 8 References
    10.     Appendix: Plots of Blocking vs Polling Performance

4.3 Efficient Power Management

Blocking and callback return behavior allow the power driver to opportunistically put the device into the idle state when the CPU is not needed. While the hardware peripheral performs the operation in the background, the power driver turn off the CPU power domain while it waits for the peripheral to trigger an interrupt upon completion of the operation.

Though polling return behavior offers the least overhead, it provides no integrated power management to place the CPU in idle state when not in use. Because the CPU is in active mode continuously polling a flag to signal the operation’s completion, there is no opportunity for the power driver to put the device into a lower power state. Because polling return behavior should only be used for short operations, the lack of power management is not a concern. The overhead of using callback or blocking return behavior outweighs any power savings derived from spending time in idle power mode for short operations.