buffer register in USART

[amitk3553]

Why we need buffer register in b/w CPU and FIFO.

Can we write directly from CPU to FIFO.

Thanks

 

[sarathhari]

There will always be a Buffer register in USART. As the name suggests it provides a synchronization b/w a controller and other device. If we directky write something the issue of clocking speed occurs. That is the speed at which CPU operates will be pretty higher than other devices. Thus the chances of losing data is invetiable. So in USART the BAUD RATE will help in this synchronization and the data is stored into the buffer register and then to the other device with the BAUD RATE (which is bits per second).

 

[amitk3553]

There will always be a Buffer register in USART. As the name suggests it provides a synchronization b/w a controller and other device. If we directky write something the issue of clocking speed occurs. That is the speed at which CPU operates will be pretty higher than other devices. Thus the chances of losing data is invetiable. So in USART the BAUD RATE will help in this synchronization and the data is stored into the buffer register and then to the other device with the BAUD RATE (which is bits per second).

Means if CPU is having 32 bits BUS,then we need buffer register(of 32 bits and as USART fifo width is of 8 bits)

and IF CPU BUS is of 8 bits,then there should no need of buffer register as we can write directly from CPU to FIFO(if fifo width=8)

 

[sarathhari]

A 32 bit controller means all the data it can process is of 32 bit and all the registers associated with that will be also 32 bit so do the buffer and other registers associated with USART.