SPRUJ53B April 2024 – September 2024 TMS320F28P550SJ , TMS320F28P559SJ-Q1
For example, multiplexing for the GPIO6 pin is controlled by writing to GPAGMUX[13:12] and GPAMUX[13:12]. By writing to these bits, GPIO6 is configured as either a general-purpose digital I/O or one of several different peripheral functions. An example of GPyGMUX and GPyMUX selection and options for a single GPIO are shown in Table 10-9.
GPAGMUX1[13:12] | GPAMUX1[13:12] | Pin Functionality |
---|---|---|
00 | 00 | GPIO6 |
00 | 01 | Peripheral 1 |
00 | 10 | Peripheral 2 |
00 | 11 | Peripheral 3 |
01 | 00 | GPIO6 |
01 | 01 | Peripheral 4 |
01 | 10 | Peripheral 5 |
01 | 11 | |
10 | 00 | GPIO6 |
10 | 01 | |
10 | 10 | Peripheral 6 |
10 | 11 | Peripheral 7 |
11 | 00 | GPIO6 |
11 | 01 | Peripheral 8 |
11 | 10 | Peripheral 9 |
11 | 11 | Peripheral 10 |
The devices have different multiplexing schemes. If a peripheral is not available on a particular device, that mux selection is reserved on that device and must not be used.
Some peripherals can be assigned to more than one pin by way of the mux registers. For example, OUTPUTXBAR1 can be assigned to GPIOs p, q, or r (where p, q, and r are example GPIO numbers), depending on individual system requirements. An example of this is shown in Table 10-10.
If none or more then one of the GPIO pins is configured as peripheral input pins, then that GPIO is set to a hard-wired default value.
GMUX Configuration | MUX Configuration | ||
---|---|---|---|
Choice 1: | GPIOp | GPyGMUX1[5:4] = 01 | GPyMUX1[5:4] = 01 |
or Choice 2: | GPIOq | GPyGMUX2[17:16] = 00 | GPyMUX2[17:16] = 01 |
or Choice 3: | GPIOr | GPyGMUX1[7:6] = 01 | GPyMUX1[7:6] = 01 |