csr_target_apb

Files
file	csr_target_apb.cdl
	Pipelined CSR request/response interface to APB slave interface.

Detailed Description

Modules

module csr_target_apb::csr_target_apb	(	clock	clk,
		input bit	reset_n,
		input t_csr_request	csr_request,
		output t_csr_response	csr_response,
		output t_apb_request	apb_request,
		input t_apb_response	apb_response,
		input bit	csr_select[16]
	)

The documentation of the pipelined CSR interface itself is in other files (at this time, csr_target_csr.cdl).

This module provides a CSR target interface, and drives out an APB master request bus. It can therefore be used at the 'leaf' end of a CSR interface tree, to access standard APB peripherals.

The module must be told which csr_select it should be listening for on the CSR target interface; it converts any read or write to an APB master request (with top 16 bits of paddr zeroed) to the APB request. Hence the APB target attached to this module is accessed by CSR requests with the select set to csr_select.

The module is lightweight, effectively being a registered end-point on the CSR interface and a registered APB request.

Parameters

[in]	clk	Clock for the CSR interface, possibly gated version of master CSR clock
[in]	reset_n	Active low reset
[in]	csr_request	Pipelined csr request interface input
[out]	csr_response	Pipelined csr request interface response
[out]	apb_request	APB request to target
[in]	apb_response	APB response from target
[in]	csr_select	Hard-wired select value for the client