SPRUJ17H March 2022 – October 2024 AM2631 , AM2631-Q1 , AM2632 , AM2632-Q1 , AM2634 , AM2634-Q1
Both the FSITX and FSIRX modules contain control registers that have embedded write protection. This is accomplished through register keys and a main register lock. These protections make sure that no spurious writes or unintentional modifications to these registers are accepted. .
Register Key Protection
Some bits in the FSI registers are protected by a key. To write to these bits, the key must be written at the same time. For example, to put the transmitter core into reset, TX_MAIN_CTRL.CORE_RST must be set. To do this, write 0xA501 to TX_MAIN_CTRL, where 0xA500 is the KEY value, and 0x0001 is the CORE_RST value. Refer to the Registers section for more information on which registers have write keys added.
Control Register Lock Protection
There also exists a main lock to prevent any modifications to the control registers. There is an independent lock for each FSI module. For the list of registers that are protected by this control register lock, refer to the Registers section. The control register lock prevents any writes to the control registers until the lock is released. To set the control register lock, write 0xA501 to RX_LOCK_CTRL and TX_LOCK_CTRL for the receiver and transmitter, respectively.
The control register lock cannot be disabled by the application until a SYSRSn has been asserted. This can occur at the device level, or by writing to the appropriate peripheral soft reset register (DEV_CFG_REGS.SOFTPRESx) for the FSI module.