ZHCSAH6F November 2012 – September 2021 TMS320F28050 , TMS320F28051 , TMS320F28052 , TMS320F28052F , TMS320F28052M , TMS320F28053 , TMS320F28054 , TMS320F28054F , TMS320F28054M , TMS320F28055
PRODUCTION DATA
Section 6.2.1 describes the signals. With the exception of the JTAG pins, the GPIO function is the default at reset, unless otherwise mentioned. The peripheral signals that are listed under them are alternate functions. Some peripheral functions may not be available in all devices. See Table 5-1 for details. Inputs are not 5-V tolerant. All GPIO pins are I/O/Z and have an internal pullup (PU), which can be selectively enabled or disabled on a per-pin basis. This feature only applies to the GPIO pins. The pullups on the PWM pins are not enabled at reset, except as noted in Section 6.2.1. The pullups on other GPIO pins are enabled upon reset.
When the on-chip VREG is used, the GPIO19, GPIO34, GPIO35, GPIO36, GPIO37, and GPIO38 pins could glitch during power up. This potential glitch will finish before the boot mode pins are read and will not affect boot behavior. If glitching is unacceptable in an application, 1.8 V could be supplied externally. Alternatively, adding a current-limiting resistor (for example, 470 Ω) in series with these pins and any external driver could be considered to limit the potential for degradation to the pin and/or external circuitry. There is no power-sequencing requirement when using an external 1.8-V supply. However, if the 3.3-V transistors in the level-shifting output buffers of the I/O pins are powered prior to the 1.8-V transistors, it is possible for the output buffers to turn on, causing a glitch to occur on the pin during power up. To avoid this behavior, power the VDD pins prior to or simultaneously with the VDDIO pins, ensuring that the VDD pins have reached 0.7 V before the VDDIO pins reach 0.7 V.