SLAA380B December   2007  – September 2018 MSP430F2616 , MSP430F2617 , MSP430F2618 , MSP430F2619

 

  1.   Migrating From MSP430F16x MCUs to MSP430F261x MCUs
    1.     Trademarks
    2. 1 Comparison of MSP430F1xx and MSP430F2xx Families
    3. 2 Hardware Considerations for MSP430F16x to MSP430F261x Migration
      1. 2.1 Device Package and Pinout
      2. 2.2 Current Consumption
      3. 2.3 Operating Frequency and Supply Voltage
      4. 2.4 Device Errata
    4. 3 MSP430F16x to MSP430F261x Migration – Firmware Considerations
      1. 3.1 CPU and Memory Considerations
        1. 3.1.1 Extended Memory Architecture
        2. 3.1.2 Subroutine Parameter Passing and Stack Frame
        3. 3.1.3 MSP430X Instruction Cycle Count Optimizations
        4. 3.1.4 Device Memory Map
        5. 3.1.5 Information Flash Memory
      2. 3.2 Serial Communication – USART Versus USCI
        1. 3.2.1 UART Mode
        2. 3.2.2 SPI Mode
        3. 3.2.3 I2C Mode
      3. 3.3 Clock System
        1. 3.3.1 LFXT1 and XT2 Oscillators
        2. 3.3.2 Digitally Controlled Oscillator (DCO)
      4. 3.4 Bootloader
      5. 3.5 Interrupt Vectors
      6. 3.6 Beware of Reserved Bits!
      7. 3.7 Timers
      8. 3.8 Analog Comparator
    5. 4 References
  2.   Revision History

3.1.3 MSP430X Instruction Cycle Count Optimizations

If the code being migrated to the MSP430F261x contains any hand-optimized timing-critical code, keep in mind that the cycle count for certain CPU instructions has been reduced by one or two cycles. However, this consideration typically applies to only assembler-coded software routines, which is the preferred method of coding anything that requires an exact prediction of CPU cycles being consumed.

Another architectural improvement that the MSP430X devices (MSP430F261x) bring is the reduced interrupt response time (five MCLK cycles instead of six), and the reduced time to return from an interrupt service function (three cycles instead of five).

Most applications being migrated transparently benefit from these cycle count reductions.