From c7c919398266b42664d6817756eae8659ab9b66c Mon Sep 17 00:00:00 2001
From: liangkangnan <liangkangnan@163.com>
Date: Sun, 8 Mar 2020 15:07:17 +0800
Subject: [PATCH] add peripheral: timer

Signed-off-by: liangkangnan <liangkangnan@163.com>
---
 rtl/perips/timer.v         | 97 ++++++++++++++++++++++++++++++++++++++
 sim/sim_default_nowave.bat |  2 +-
 sim/sim_new_nowave.bat     |  2 +-
 3 files changed, 99 insertions(+), 2 deletions(-)
 create mode 100644 rtl/perips/timer.v

diff --git a/rtl/perips/timer.v b/rtl/perips/timer.v
new file mode 100644
index 0000000..d3c35d6
--- /dev/null
+++ b/rtl/perips/timer.v
@@ -0,0 +1,97 @@
+ /*                                                                      
+ Copyright 2020 Blue Liang, liangkangnan@163.com
+                                                                         
+ Licensed under the Apache License, Version 2.0 (the "License");         
+ you may not use this file except in compliance with the License.        
+ You may obtain a copy of the License at                                 
+                                                                         
+     http://www.apache.org/licenses/LICENSE-2.0                          
+                                                                         
+ Unless required by applicable law or agreed to in writing, software    
+ distributed under the License is distributed on an "AS IS" BASIS,       
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and     
+ limitations under the License.                                          
+ */
+
+
+// 32 bits count up timer module
+module timer (
+
+    input wire clk,
+    input wire rst,
+
+    input wire[31:0] wdata,
+    input wire[31:0] waddr,
+    input wire[31:0] raddr,
+    input wire we,
+
+    output reg[31:0] rdata,
+    output wire int_sig
+
+    );
+
+    // timer expired value
+    // addr: 0x10000008
+    reg[31:0] timer_value;
+
+    // timer current count, read only
+    // addr: 0x10000004
+    reg[31:0] timer_count;
+
+    // [0]: timer enable
+    // [1]: timer int enable
+    // [2]: timer int pending, write 1 to clear it
+    // addr: 0x10000000
+    reg[31:0] timer_ctrl;
+
+
+    assign int_sig = ((timer_ctrl[0] == 1'b1) && (timer_ctrl[1] == 1'b1) && (timer_ctrl[2] == 1'b1)) ? 1'b1 : 1'b0;
+
+    // write timer regs
+    always @ (posedge clk) begin
+        if (rst == 1'b0) begin
+            timer_count <= 32'h0;
+            timer_value <= 32'h0;
+            timer_ctrl <= 32'h0;
+        end else begin
+            if (timer_ctrl[0] == 1'b1) begin
+                timer_count <= timer_count + 1'b1;
+                if (timer_count == timer_value) begin
+                    timer_ctrl[2] <= 1'b1;
+                    timer_count <= 32'h0;
+                end
+            end
+            if (we == 1'b1) begin
+                if (waddr == 32'h10000008) begin
+                    timer_value <= wdata;
+                end else if (waddr == 32'h10000000) begin
+                    if (wdata[2] == 1'b0) begin
+                        timer_ctrl <= wdata;
+                    // write 1 to clear pending
+                    end else begin
+                        timer_ctrl <= {wdata[31:3], 1'b0, wdata[1:0]};
+                    end
+                end
+            end
+        end
+    end
+
+    // read timer regs
+    always @ (*) begin
+        if (rst == 1'b0) begin
+            rdata <= 32'h0;
+        end else begin
+            if (raddr == 32'h10000008) begin
+                rdata <= timer_value;
+            end else if (raddr == 32'h10000000) begin
+                rdata <= timer_ctrl;
+            end else if (raddr == 32'h10000004) begin
+                rdata <= timer_count;
+            end else begin
+                rdata <= 32'h0;
+            end
+        end
+    end
+
+endmodule
diff --git a/sim/sim_default_nowave.bat b/sim/sim_default_nowave.bat
index 47884d3..c9f0b8f 100644
--- a/sim/sim_default_nowave.bat
+++ b/sim/sim_default_nowave.bat
@@ -1,2 +1,2 @@
-iverilog -s tinyriscv_core_tb -o out.vvp -I ..\rtl\core tinyriscv_core_tb.v ..\rtl\core\defines.v ..\rtl\core\ex.v ..\rtl\core\id.v ..\rtl\core\tinyriscv_core.v ..\rtl\core\pc_reg.v ..\rtl\core\regs.v ..\rtl\core\sim_ram.v ..\rtl\core\if_id.v ..\rtl\core\div.v ..\rtl\debug\jtag_dm.v ..\rtl\debug\jtag_driver.v ..\rtl\debug\jtag_top.v
+iverilog -s tinyriscv_core_tb -o out.vvp -I ..\rtl\core tinyriscv_core_tb.v ..\rtl\core\defines.v ..\rtl\core\ex.v ..\rtl\core\id.v ..\rtl\core\tinyriscv_core.v ..\rtl\core\pc_reg.v ..\rtl\core\regs.v ..\rtl\core\sim_ram.v ..\rtl\core\if_id.v ..\rtl\core\div.v ..\rtl\debug\jtag_dm.v ..\rtl\debug\jtag_driver.v ..\rtl\debug\jtag_top.v ..\rtl\perips\timer.v
 vvp out.vvp
diff --git a/sim/sim_new_nowave.bat b/sim/sim_new_nowave.bat
index d1a5a83..9d5f179 100644
--- a/sim/sim_new_nowave.bat
+++ b/sim/sim_new_nowave.bat
@@ -1,3 +1,3 @@
 ..\tools\BinToMem_CLI.exe %1 %2
-iverilog -s tinyriscv_core_tb -o out.vvp -I ..\rtl\core tinyriscv_core_tb.v ..\rtl\core\defines.v ..\rtl\core\ex.v ..\rtl\core\id.v ..\rtl\core\tinyriscv_core.v ..\rtl\core\pc_reg.v ..\rtl\core\regs.v ..\rtl\core\sim_ram.v ..\rtl\core\if_id.v ..\rtl\core\div.v ..\rtl\debug\jtag_dm.v ..\rtl\debug\jtag_driver.v ..\rtl\debug\jtag_top.v
+iverilog -s tinyriscv_core_tb -o out.vvp -I ..\rtl\core tinyriscv_core_tb.v ..\rtl\core\defines.v ..\rtl\core\ex.v ..\rtl\core\id.v ..\rtl\core\tinyriscv_core.v ..\rtl\core\pc_reg.v ..\rtl\core\regs.v ..\rtl\core\sim_ram.v ..\rtl\core\if_id.v ..\rtl\core\div.v ..\rtl\debug\jtag_dm.v ..\rtl\debug\jtag_driver.v ..\rtl\debug\jtag_top.v ..\rtl\perips\timer.v
 vvp out.vvp