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simple_pic/trunk Property changes : Added: svn:mergeinfo ## -0,0 +0,0 ## Index: simple_pic/web_uploads =================================================================== --- simple_pic/web_uploads (nonexistent) +++ simple_pic/web_uploads (revision 6)

simple_pic/web_uploads Property changes : Added: svn:mergeinfo ## -0,0 +0,0 ## Index: simple_pic/branches =================================================================== --- simple_pic/branches (nonexistent) +++ simple_pic/branches (revision 6)

simple_pic/branches Property changes : Added: svn:mergeinfo ## -0,0 +0,0 ## Index: simple_pic/tags/initial/rtl/simple_pic.v =================================================================== --- simple_pic/tags/initial/rtl/simple_pic.v (nonexistent) +++ simple_pic/tags/initial/rtl/simple_pic.v (revision 6) @@ -0,0 +1,241 @@ +///////////////////////////////////////////////////////////////////// +//// //// +//// OpenCores Simple Programmable Interrupt Controller //// +//// //// +//// Author: Richard Herveille //// +//// richard@asics.ws //// +//// www.asics.ws //// +//// //// +///////////////////////////////////////////////////////////////////// +//// //// +//// Copyright (C) 2002 Richard Herveille //// +//// richard@asics.ws //// +//// //// +//// 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 SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY //// +//// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED //// +//// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS //// +//// FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHOR //// +//// OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, //// +//// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES //// +//// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE //// +//// GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR //// +//// BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF //// +//// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT //// +//// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT //// +//// OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE //// +//// POSSIBILITY OF SUCH DAMAGE. //// +//// //// +///////////////////////////////////////////////////////////////////// + +// CVS Log +// +// $Id: simple_pic.v,v 1.1.1.1 2002-12-02 17:19:58 rherveille Exp $ +// +// $Date: 2002-12-02 17:19:58 $ +// $Revision: 1.1.1.1 $ +// $Author: rherveille $ +// $Locker: $ +// $State: Exp $ +// + + + +// +// This is a simple Programmable Interrupt Controller. +// The number of interrupts is depending on the databus size. +// There's one interrupt input per databit (i.e. 16 interrupts for a 16 +// bit databus). +// All attached devices share the same CPU priority level. +// +// +// +// Registers: +// +// 0x00: EdgeEnable Register +// bits 7:0 R/W Edge Enable '1' = edge triggered interrupt source +// '0' = level triggered interrupt source +// 0x02: PolarityRegister +// bits 7:0 R/W Polarity '1' = high level / rising edge +// '0' = low level / falling edge +// 0x03: MaskRegister +// bits 7:0 R/W Mask '1' = interrupt masked (disabled) +// '0' = interrupt not masked (enabled) +// 0x04: PendingRegister +// bits 7:0 R/W Pending '1' = interrupt pending +// '0' = no interrupt pending +// +// A CPU interrupt is generated when an interrupt is pending and its +// MASK bit is cleared. +// +// +// +// HOWTO: +// +// Clearing pending interrupts: +// Writing a '1' to a bit in the interrupt pending register clears the +// interrupt. Make sure to clear the interrupt at the source before +// writing to the interrupt pending register. Otherwise the interrupt +// will be set again. +// +// Priority based interrupts: +// Upon reception of an interrupt, check the interrupt register and +// determine the highest priority interrupt. Mask all interrupts from the +// current level to the lowest level. This negates the interrupt line, and +// makes sure only interrupts with a higher level are triggered. After +// completion of the interrupt service routine, clear the interrupt source, +// the interrupt bit in the pending register, and restore the MASK register +// to it's previous state. +// +// Addapt the core for fewer interrupt sources: +// If less than 8 interrupt sources are required, than the 'is' parameter +// can be set to the amount of required interrupts. Interrupts are mapped +// starting at the LSBs. So only the 'is' LSBs per register are valid. All +// other bits (i.e. the 8-'is' MSBs) are set to zero '0'. +// Codesize is approximately linear to the amount of interrupts. I.e. using +// 4 instead of 8 interrupt sources reduces the size by approx. half. +// + + +// synopsys translate_off +`include "timescale.v" +// synopsys translate_on + +module simple_pic( + clk_i, rst_i, cyc_i, stb_i, adr_i, we_i, dat_i, dat_o, ack_o, int_o, + irq +); + + parameter is = 8; // Number of interrupt sources + + // + // Inputs & outputs + // + + // 8bit WISHBONE bus slave interface + input clk_i; // clock + input rst_i; // reset (asynchronous active low) + input cyc_i; // cycle + input stb_i; // strobe (cycle and strobe are the same signal) + input [ 2:1] adr_i; // address + input we_i; // write enable + input [ 7:0] dat_i; // data output + output [ 7:0] dat_o; // data input + output ack_o; // normal bus termination + + output int_o; // interrupt output + + // + // Interrupt sources + // + input [is:1] irq; // interrupt request inputs + + + // + // Module body + // + reg [is:1] pol, edgen, pending, mask; // register bank + reg [is:1] lirq, dirq; // latched irqs, delayed latched irqs + + + // + // perform parameter checks + // + // synopsys translate_off + initial + begin + if(is > 8) + $display("simple_pic: max. 8 interrupt sources supported."); + end + // synopsys translate_on + + // + // latch interrupt inputs + always @(posedge clk_i) + lirq <= #1 irq; + + // + // generate delayed latched irqs + always @(posedge clk_i) + dirq <= #1 lirq; + + + // + // generate actual triggers + function trigger; + input edgen, pol, lirq, dirq; + + reg edge_irq, level_irq; + begin + edge_irq = pol ? (lirq & ~dirq) : (dirq & ~lirq); + level_irq = pol ? lirq : ~lirq; + + trigger = edgen ? edge_irq : level_irq; + end + endfunction + + reg [is:1] irq_event; + integer n; + always @(posedge clk_i) + for(n=1; n<=is; n=n+1) + irq_event[n] <= #1 trigger(edgen[n], pol[n], lirq[n], dirq[n]); + + // + // generate wishbone register bank writes + wire wb_acc = cyc_i & stb_i; // WISHBONE access + wire wb_wr = wb_acc & we_i; // WISHBONE write access + + always @(posedge clk_i or negedge rst_i) + if (~rst_i) + begin + pol <= #1 {{is}{1'b0}}; // clear polarity register + edgen <= #1 {{is}{1'b0}}; // clear edge enable register + mask <= #1 {{is}{1'b1}}; // mask all interrupts + end + else if(wb_wr) // wishbone write cycle?? + case (adr_i) // synopsys full_case parallel_case + 2'b00: edgen <= #1 dat_i[is-1:0]; // EDGE-ENABLE register + 2'b01: pol <= #1 dat_i[is-1:0]; // POLARITY register + 2'b10: mask <= #1 dat_i[is-1:0]; // MASK register + 2'b11: ; // PENDING register is a special case (see below) + endcase + + + // pending register is a special case + always @(posedge clk_i or negedge rst_i) + if (~rst_i) + pending <= #1 {{is}{1'b0}}; // clear all pending interrupts + else if ( wb_wr & &adr_i ) + pending <= #1 (pending & ~dat_i[is-1:0]) | irq_event; + else + pending <= #1 pending | irq_event; + + // + // generate dat_o + reg [7:0] dat_o; + always @(posedge clk_i) + case (adr_i) // synopsys full_case parallel_case + 2'b00: dat_o <= #1 { {{8-is}{1'b0}}, edgen}; + 2'b01: dat_o <= #1 { {{8-is}{1'b0}}, pol}; + 2'b10: dat_o <= #1 { {{8-is}{1'b0}}, mask}; + 2'b11: dat_o <= #1 { {{8-is}{1'b0}}, pending}; + endcase + + // + // generate ack_o + reg ack_o; + always @(posedge clk_i) + ack_o <= #1 wb_acc & !ack_o; + + // + // generate CPU interrupt signal + reg int_o; + always @(posedge clk_i) + int_o <= #1 |(pending & ~mask); + +endmodule + Index: simple_pic/tags =================================================================== --- simple_pic/tags (nonexistent) +++ simple_pic/tags (revision 6)

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