Subversion Repositories apbi2c

//////////////////////////////////////////////////////////////////

////

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////    APB module to I2C Core

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////

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//// This file is part of the APB to I2C project

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//// http://www.opencores.org/cores/apbi2c/

////

////

////

//// Description

////

//// Implementation of APB IP core according to

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//// apbi2c_spec IP core specification document.

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////

////

//// To Do: Things are right here but always all block can suffer changes

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////

////

////

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//// Author(s): - Felipe Fernandes Da Costa, fefe2560@gmail.com

////              Ronal Dario Celaya

////

///////////////////////////////////////////////////////////////// 

////

////

//// Copyright (C) 2009 Authors and OPENCORES.ORG

////

////

////

//// This source file may be used and distributed without

////

//// restriction provided that this copyright statement is not

////

//// removed from the file and that any derivative work contains

//// the original copyright notice and the associated disclaimer.

////

////

//// This source file is free software; you can redistribute it

////

//// and/or modify it under the terms of the GNU Lesser General

////

//// Public License as published by the Free Software Foundation;

//// either version 2.1 of the License, or (at your option) any

////

//// later version.

////

////

////

//// This source is distributed in the hope that it will be

////

//// useful, but WITHOUT ANY WARRANTY; without even the implied

////

//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR

////

//// PURPOSE. See the GNU Lesser General Public License for more

//// details.

////

////

////

//// You should have received a copy of the GNU Lesser General

////

//// Public License along with this source; if not, download it

////

//// from http://www.opencores.org/lgpl.shtml

////

////

///////////////////////////////////////////////////////////////////

`timescale 1ns/1ps //timescale 

module apb(

                        //standard ARM

                        input PCLK,

                        input PRESETn,

                        input PSELx,

                        input PWRITE,

                        input PENABLE,

                        input [31:0] PADDR,

                        input [31:0] PWDATA,

                        //internal pin

                        input [31:0] READ_DATA_ON_RX,

                        input ERROR,

                        input TX_EMPTY,

                        input RX_EMPTY,

                        //external pin

                        output [31:0] PRDATA,

                        //internal pin 

                        output reg [13:0] INTERNAL_I2C_REGISTER_CONFIG,

                        output reg [13:0] INTERNAL_I2C_REGISTER_TIMEOUT,

                        output [31:0] WRITE_DATA_ON_TX,

                        output  WR_ENA,

                        output  RD_ENA,

                        //outside port 

                        output PREADY,

                        output PSLVERR,

                        //interruption

                        output INT_RX,

                        output INT_TX

          );

//ENABLE WRITE ON TX FIFO

assign WR_ENA = (PWRITE == 1'b1 & PENABLE == 1'b1 & PADDR == 32'd0 & PSELx == 1'b1)?  1'b1:1'b0;

//ENABLE READ ON RX FIFO

assign RD_ENA = (PWRITE == 1'b0 & PENABLE == 1'b1  & PADDR == 32'd4 & PSELx == 1'b1)?  1'b1:1'b0;

//WRITE ON I2C MODULE

assign PREADY = ((WR_ENA == 1'b1 | RD_ENA == 1'b1 | PADDR == 32'd8 | PADDR == 32'd12) &  (PENABLE == 1'b1 & PSELx == 1'b1))? 1'b1:1'b0;

//INPUT TO WRITE ON TX FIFO

assign WRITE_DATA_ON_TX = (PADDR == 32'd0)? PWDATA:PWDATA;

//OUTPUT DATA FROM RX TO PRDATA

assign PRDATA = (PADDR == 32'd4)? READ_DATA_ON_RX:READ_DATA_ON_RX;

//ERROR FROM I2C CORE

assign PSLVERR = ERROR;

//INTERRUPTION FROM I2C

assign INT_TX = TX_EMPTY;

//INTERRUPTION FROM I2C

assign INT_RX = RX_EMPTY;

//This is sequential logic used only to register configuration

always@(posedge PCLK)

begin

        if(!PRESETn)

        begin

                INTERNAL_I2C_REGISTER_CONFIG <= 14'd0;

                INTERNAL_I2C_REGISTER_TIMEOUT <= 14'd0;

        end

        else

        begin

                // Set configuration to i2c

                if(PADDR == 32'd8 && PSELx == 1'b1 && PWRITE == 1'b1 && PREADY == 1'b1)

                begin

                        INTERNAL_I2C_REGISTER_CONFIG <= PWDATA[13:0];

                end

                else if(PADDR == 32'd12 && PSELx == 1'b1 && PWRITE == 1'b1 && PREADY == 1'b1)

                begin

                        INTERNAL_I2C_REGISTER_TIMEOUT <= PWDATA[13:0];

                end

                else

                begin

                        INTERNAL_I2C_REGISTER_CONFIG <= INTERNAL_I2C_REGISTER_CONFIG;

                end

        end

end

endmodule