COUNTDOWN | |
Class | I/O Registers, Interrupt |
Base Address | IoBaseAddress register value |
Address Offset | 0x48 |
Access Mode | Read/Write |
Width | 16 bits |
Countdown is a programmable down-counter that will generate an interrupt upon its expiration. If the CountdownIntEnable bit in DMACtrl is set, the IntRequested interrupt will be generated when Countdown counts through zero. Countdown has two modes of operation that is selected by the CountdownMode bit in DMACtrl.When CountdownMode is cleared, Countdown is loaded by the host software with an initial countdown value, then decrements at a rate determined by the CountdownSpeed bit in DMACtrl. When CountdownSpeed is cleared, the count rate is once every 3.2 us. When CountdownSpeed is set, the count rate is once every 320 ns. When Countdown reaches zero, it continues to count down, wrapping to 0xffff. When CountdownMode is set, Countdown begins counting only when TxDMAComplete in IntStatus becomes set. Countdown is cleared by reset.
BIT DESCRIPTION
Value of current state of Countdown timer.
