Hard Processor System Technical Reference Manual: Agilex™ 5 SoCs

ID 814346
Date 7/19/2024
Public

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5.3.7.1.2. Programming Command Registers

As indicated previously, all operations in the NAND Flash controller are executed by the command engine module. This supports up to 8 execution threads, but the command engine can only accept a new command when the thread selected is in IDLE state. Follow this sequence to start a new operation on a specific thread number:

  1. Check if the thread selected is in IDLE state. For this, the trd_status register (0x0120) needs to be read. Each bit in the trd_busy field corresponds to the state of a thread (that is, bit0 is for thread 0, bit1 is for thread 1, and so on). If the corresponding bit is cleared, then we can start a new operation in that thread.
  2. Write the operation to trigger in the command registers (0 to 6, registers may be in cmd_regX registers or in descriptors depending on the operation mode), writing last the command register 0 (writing in this register the thread number in the TRD_NUM field), as this write operation triggers the operation execution.