28-03-2014, 11:39 AM
Register Transfer Languages (RTL)
Register Transfer.ppt (Size: 137.5 KB / Downloads: 103)
Basic Definitions
Digital system is a collection of digital hardware modules
Modules are registers, counters, arithmetic elements, etc connected via:
- data paths routes on which information is moved
- control paths routes on which control signals are moved
Micro operations (micro-ops) are operations on data stored in registers
Digital modules (often just called “registers”) are defined by their information contents and the set of micro-ops they perform
Register transfer language is a concise and precise means of describing those operations
What is Register Transfer Language?
Register Transfer Language (RTL): used to describe CPU organization in high-level terms
RTL expressions are made up of elements which describe the registers being manipulated, and the micro-ops being performed on them
Micro-Ops Transfer
Bus
A bus consists of a set of parallel data lines
To transfer data using a bus: connect the output of the source register to the bus; connect the input of the target register to the bus; when the clock pulse arrives, the transfer occurs
Micro-Ops Transfer
Memory
Memory transfers are similar to register transfers, but…
Memory to register transfers are called read operations, while register to memory transfers are called write operations
RTL expressions for a read operation, assuming the use of an address registers:
AR <- address
DR <- M[AR]
RTL expressions for a write operation, assuming use of a data register:
AR <- address
DR <- value
M[AR] <- DR