SPRUJ53B April 2024 – September 2024 TMS320F28P550SJ , TMS320F28P559SJ-Q1
The FSI module in this device supports multi-node TDM configurations, whereas a single main device can control multiple remote node devices. To use the FSI module in the multi-node TDM configuration described, the remote node device must utilize tag matching and user data filtering.
This multi-node TDM configuration is supported in the FSI module through time-division multiplexing. When TDM is enabled, each remote node device must also have tag matching enabled. Figure 25-10 shows a scheme where a single main device is communicating with multiple remote node devices. All FSI receive modules in the remote node devices are directly connected to the main device transmit module. The transmit modules of the remote node devices are chained serially such that each transmit module is connected to the next remote node device and the last remote node device output connects to the main device receive module. Each remote node device decides, based on the received frame's tag, whether to transmit the data or to enter bypass mode where the previous remote node device transmit module directly connects to the next remote node device. This is done by using the FSI transmit module TDM_IN.
When an FSI transmitter module is used in TDM mode, TXCLK_TDM_IN, TXD0_TDM_IN and TXD1_TDM_IN pins are used if the transmitter is required to enter bypass mode. Figure 25-11 shows how the FSI module operates when in multi-node TDM mode.
The SEL_TDM_PATH signal is sourced from the CLB module. The CLB module also generates the transmit trigger for the FSI transmitter. The CLB module must be configured to decide when to generate the FSI transmit trigger based on the status of the data, ping, and frame tag match generated by the FSI receiver module. The FSITX module must be configured to transmit on an external trigger and the corresponding CLB trigger input must be selected. In a broadcast scenario (FSI tag match notifies all remote node devices that a match has occurred), the CLB module inside each remote node device generates a trigger and SEL_TDM_PATH signal. The main key here is that the trigger and the SEL_TDM_PATH signal must be generated at a different time interval in a non-overlapping manner. Figure 25-12 shows an example of FSI transmit triggers and the multi-node TDM SEL_TDM_PATH signals generated by the RX_TRIGx signal or the CLB module of the remote node devices in a broadcast scenario.