In the FSI TX module, use the following example to setup and run FSI from Arm without interrupt:

fsi_loopback_polling (ti.com)

In addition, PRU executes the time trigger, sending data using the IEP timer and task manager. Figure 2-1 shows the design process of the FSI TX module.

Figure 2-1 FSI TX Module Design Process

The specific steps to use the IEP to trigger FSI transmitting are listed in the following bullets:

1. Init IEP timer – set the clock to 333 MHz, cmp0 wrap around, the count value is set to 3 to achieve a count of 1 approximately equal to 1ns, so that cmp 0- 7 values can be set easily
2. Init task manager with cmpx_hit trigger
3. Enable task manager
4. Enable IEP timer
5. For debug use PRU_GPO to send a pulse

Figure 2-2 shows the IEP timer configuration.

Figure 2-2 IEP Timer Configuration

In terms of configuration of the FSI TX module, refer to the following paths to find the R5F source code:

And rewrite the code with C or assembly language in ICSSG.