A 16- bit DMA device is operating in cycle stealing mode. Each DM
| A 16- bit DMA device is operating in cycle stealing mode. Each DMA cycle is of 9 cycle state and DMA clock is 3 MHz, if the processor cycle takes 1 μs then what is the DMA transfer rate?
A. 25 × 10<sup>4</sup> Word/second
B. 50 × 10<sup>4</sup> Word/second
C. 25 × 10<sup>3</sup> Word/second
D. 50 × 10<sup>3</sup> Word/second
Please scroll down to see the correct answer and solution guide.
Right Answer is: A
SOLUTION
In cycle stealing mode, 1 word is transfer at a time.
Transfer time for DMA = \(\frac{9}{{3\; \times \;{{10}^6}\;}} = 3\;\mu s\)
Processor time = 1 μs
Total transfer time per word = 1 + 3 = 4 μs
∴ 4 μs = 1 W
∴ Transfer rate = \(25 \times {10^4}\;W/s\)