SPRUJ53B April 2024 – September 2024 TMS320F28P550SJ , TMS320F28P559SJ-Q1
On reset, GPIOs are in input mode and have the internal pullups disabled. An un-driven input can float to a mid-rail voltage and cause wasted shoot-through current on the input buffer. The user must always put each GPIO in one of these configurations:
On devices with lesser pin count packages, pull-ups on unbonded GPIOs are by default enabled to prevent floating inputs. The user must take care to avoid disabling these pullups in the application code.
On devices with larger pin count packages, the pullups for any internally unbonded GPIO must be enabled to prevent floating inputs. TI has provided functions in controlSUITE/C2000Ware that users can call to enable the pullup on any unbonded GPIO for the package in use. This function, GPIO_EnabledUnbondedIOPullups(), resides in the (Device)_Sysctrl.c file and is called by default from InitSysCtrl(). The user must take care to avoid disabling these pullups in the application code.