SPRUIX1B October 2022 – April 2024 TMS320F2800132 , TMS320F2800133 , TMS320F2800135 , TMS320F2800137
To improve the accuracy of INTOSC2, an external resistor (ExtR) mode can be used. This mode allows for a highly accurate external resistor to be added to the board and connected to the ExtR-capable pin. See the TMS320F280013x Real-Time Microcontrollers Data Sheet for which pin is ExtR-capable on each package.
The INTOSC2 starts up in internal resistor mode, and therefore does not utilize the ExtR by default. When using the standard internal resistor, INTOSC2 is still fully functional, but with performance less than that of an accurate ExtR. This can be changed to use a more accurate external resistor (ExtR) by setting the CLK_CFG_REGS CLKSRCCTL1.INTOSC2CLKMODE bit to be 1. For more details on correctly enabling ExtR functionality, please see Section 3.7.9.