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
Up to twelve independent peripheral signals are multiplexed on a single GPIO-enabled pin in addition to the CPU-controlled I/O capability. Each pin output can be controlled by either a peripheral or one of the two CPU masters.
There are up to 8 possible I/O ports:
The analog signals on this device are multiplexed with digital inputs. These analog IO (AIO) pins do not have digital output capability. The analog IO (AIO) pins are assigned to a single port:
Figure 8-1 shows the GPIO logic for a single pin.
There are two key features to note in Figure 8-1. The first is that the input and output paths are entirely separate, connecting only at the pin. The second is that peripheral muxing takes place far from the pin. As a result, for both CPUs and CLAs to read the physical state of the pin independent of CPU mastering and peripheral muxing is possible. Likewise, external interrupts can be generated from peripheral activity. All pin options such as input qualification and open-drain output are valid for all masters and peripherals. However, the peripheral muxing, CPU muxing, and pin options can only be configured by CPU1.
JTAG uses a different signal path that does not support inversion or qualification.
GPIO22 and GPIO23 are in a special analog mode at reset, and must be reconfigured for GPIO use by disabling DC-DC and clearing the bits in GPAAMSEL. GPIO23 maximum toggle frequency is limited. This is estimated to be 12MHz.
GPIO18/X2 has different timings due to the load placed on GPIO18/X2 by the oscillator circuit. For information on using GPIO18/X2 as a GPIO, see the data sheet and the Clocking section of this document.
If digital signals with sharp edges (high dv/dt) are connected to the AIOs, cross-talk can occur with adjacent analog signals. Therefore, limit the edge rate of signals connected to AIOs if adjacent channels are being used for analog functions.