SPRUJ53C April 2024 – February 2025 TMS320F28P550SG , TMS320F28P550SJ , TMS320F28P559SG-Q1 , TMS320F28P559SJ-Q1
Memory-mapped registers in the system control operate on INTOSC1 clock domain. Any CPU writes to these registers requires a delay in between subsequent writes; otherwise, a second write can be lost. The application needs to take this into consideration and add a delay in terms of the number of NOP instructions after every write to the registers listed in Table 3-18. The formula to compute the delay between subsequent writes:
Delay (in SYSCLK cycles) = 3 × (FSYSCLK ÷ FINTOSC1) + 9
For Example: for SYSCLK = 100MHz
Delay (in SYSCLK cycles) = 3 × (100MHz ÷ 10MHz) + 9 = 39 SYSCLK cycles
| Registers requiring delay after every write |
|---|
| AUXCLKDIVSEL |
| CLBCLKCTL |
| PERCLKDIVSEL |
| SYSCLKDIVSEL |
| SYSPLLCTL1 |
| SYSPLLMULT |
| WDCR |
| XCLKOUTDIVSEL |
| XTALCR |
| CLKSRCCTL1 |
| CLKSRCCTL2 |
| CLKSRCCTL3 |
| CPU1TMR2CTL |