# Bnx System Abstraction Layer

**S**ystem **A**bstraction library abstracts a system. 
It provides interfaces to HAL layer above such that
HAL layer above is void of any core and system specific information and core and 
system agnostic. However RISC-V standard specific core details that are common acrosss all RISC-V cores are part of **C**ommon **C**ore **A**bstraction **L**ayer. 
 System Abstraction Layer abstracts a system and Core Abstraction Layer abstracts a core.
 
 # Example 
**E31** - a core and its abstracted in Core Abstraction Layer. <br>
**FE310** - a system with E31 core and peripherals is abstracted in System Abstraction Layer. <br>
 <br>
SAL dont cover that are abstracted in CAL instead might use them. 
In software architecture, CAL & SAL are beside each other as below.
 
```
---------------- Hardware Abstraction Layer --------------------------
----------------------------------------------------------------------
| System Abstraction Layer |  Core Abstraction Layer
----------------------------------------------------------------------
```

SAL abstracts: <br>
> **G**pio <br>
> **U**art <br>
> **S**pi <br>
> **I**2c <br>

Whereas CAL abstracts: <br>
> **C**ore Clock <br>
> **C**ore Boot <br>