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AT91: DIfference between APB and ASB?

Started by Mayank Kaushik January 21, 2005
Hi,

Im working with the AT91RM9200. I am confused about the distinction
between the Advanced Peripheral Bus and the Advanced System Bus..what
are they used for?

Someone kindly elaborate
Thanx
Mayank

"Mayank Kaushik" <prehistorictoad2k@yahoo.com> wrote in message news:<1106284619.910169.313640@f14g2000cwb.googlegroups.com>...
> Hi, > > Im working with the AT91RM9200. I am confused about the distinction > between the Advanced Peripheral Bus and the Advanced System Bus..what > are they used for? >
APB is simpler (no burst transfers etc) and slower than the ASB. Typically APB is used for stuff like UARTs, whereas as ASB will be used for RAM. http://www.arm.com/documentation/SoC/index.html Cheers, Jon
"Mayank Kaushik" <prehistorictoad2k@yahoo.com> skrev i meddelandet
news:1106284619.910169.313640@f14g2000cwb.googlegroups.com...
> Hi, > > Im working with the AT91RM9200. I am confused about the distinction > between the Advanced Peripheral Bus and the Advanced System Bus..what > are they used for? >
The ARM AMBA divides the busses into the ASB (Advanced System Bus) which is a 32 bit synchronous pipelined bus, and the APB which is a 16 bit non pipelined bus asynchronous bus. The CPU and memories are on the ASB and most peripherals are on the APB. There is a bridge betweeen the ASB and the APB. The reason for the APB is that the buffering reduces the complexity of peripheral and mimizes the capacitance on the ASB. The ASB is replaced by the AHB in the AMBA - II architecture.
> Someone kindly elaborate > Thanx > Mayank >