2.5 Interrupt sources

The internal generic APB registers in GFC-100 generate an interrupt request that is triggered by several sources.

Command Accept (CMD_ACCEPT_IRQ)

CMD_ACCEPT_IRQ can speed up APB master accesses to the embedded Flash. CMD_ACCEPT_IRQ is set when the CTRL register accepts a write command, asserts the fready signal on the GFB interface, and Flash executes the command. In this state, a new command can be written to the CTRL register where it enters a pending state, enabling back-to-back transfers to be executed. This behavior enables the use of the ROW WRITE command on the GFB.

When back-to-back transfers are used and if CMD_ACCEPT_IRQ and CMD_SUCCESS_IRQ or CMD_FAIL_IRQ are both set, both interrupt sources trigger together.

Command Success (CMD_SUCCESS_IRQ)

The CMD_SUCCESS_IRQ indicates the successful finish of an executed command. It makes the driver aware of the result immediately the command finishes, and prevents new transfers from the APB side being written to the CTRL register.

Command Fail (CMD_FAIL_IRQ)

The CMD_FAIL_IRQ indicates the unsuccessful finish of an executed command. It makes the driver aware of the result immediately the command finishes, and prevents new transfers from the APB side being written to the CTRL register.

Command Reject (CMD_REJECT_IRQ)

The CMD_REJECT_IRQ indicates a programming fault when software tries to modify the content of the CTRL, ADDR, and DATA0 registers either while a command is pending in the CTRL register, or when one or more interrupts are pending. The write is ignored but CMD_REJECT_IRQ indicates the error for debug purposes.

Read Overflow (READ_OVERFLOW_IRQ)

The READ_OVERFLOW_IRQ indicates that the result of a Read command cannot be updated immediately in the IRQ_STATUS register, and the Read enters the finished state. Hardware assumes this state to be an overflow situation because the new data is lost, and the hardware cannot be sure that all previous results were read by software.

Interrupt request signal

The interrupt request signal is described in A.8 System interface signals.

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