SPRUI33H November 2015 – June 2024 TMS320F280040-Q1 , TMS320F280040C-Q1 , TMS320F280041 , TMS320F280041-Q1 , TMS320F280041C , TMS320F280041C-Q1 , TMS320F280045 , TMS320F280048-Q1 , TMS320F280048C-Q1 , TMS320F280049 , TMS320F280049-Q1 , TMS320F280049C , TMS320F280049C-Q1
At power-up, the device is clocked from an on-chip 10MHz oscillator (INTOSC2). INTOSC2 is the primary internal clock source and is the default system clock at reset. INTOSC2 is used to run the boot ROM and can be used as the system clock source for the application. Note that the INTOSC2 frequency tolerance is too loose to meet the timing requirements for CAN. Use of the CAN modules requires an external oscillator. When INTOSC2 is used as the system clock source, GPIO18 (X2) is available for use as a GPIO. A 1k pull-down resistor must be connected to X1. GPIO18 has different electrical characteristics from the other GPIOs due to interaction with the oscillator circuit. For more information, see the TMS320F28004x Real-Time Microcontrollers Data Sheet.