Entity: neorv32_mtime
- File: neorv32_mtime.vhd
Diagram
Description
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<< NEORV32 - Machine System Timer (MTIME) >>
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Compatible to RISC-V spec's 64-bit MACHINE system timer including "mtime[h]" & "mtimecmp[h]".
Note: The 64-bit counter and compare systems are de-coupled into two 32-bit systems.
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BSD 3-Clause License
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Copyright (c) 2021, Stephan Nolting. All rights reserved.
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Redistribution and use in source and binary forms, with or without modification, are
permitted provided that the following conditions are met:
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1. Redistributions of source code must retain the above copyright notice, this list of
conditions and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright notice, this list of
conditions and the following disclaimer in the documentation and/or other materials
provided with the distribution.
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3. Neither the name of the copyright holder nor the names of its contributors may be used to
endorse or promote products derived from this software without specific prior written
permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS
OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
COPYRIGHT HOLDER 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.
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The NEORV32 Processor - https://github.com/stnolting/neorv32 (c) Stephan Nolting
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Ports
| Port name | Direction | Type | Description |
|---|---|---|---|
| clk_i | in | std_ulogic | global clock line |
| addr_i | in | std_ulogic_vector(31 downto 0) | address |
| rden_i | in | std_ulogic | read enable |
| wren_i | in | std_ulogic | write enable |
| data_i | in | std_ulogic_vector(31 downto 0) | data in |
| data_o | out | std_ulogic_vector(31 downto 0) | data out |
| ack_o | out | std_ulogic | transfer acknowledge |
| time_o | out | std_ulogic_vector(63 downto 0) | current system time |
| irq_o | out | std_ulogic | interrupt request |
Signals
| Name | Type | Description |
|---|---|---|
| acc_en | std_ulogic | module access enable |
| addr | std_ulogic_vector(31 downto 0) | access address |
| wren | std_ulogic | module access enable |
| mtime_lo_we | std_ulogic | time write access buffer -- |
| mtime_hi_we | std_ulogic | |
| mtimecmp_lo | std_ulogic_vector(31 downto 0) | accessible regs -- |
| mtimecmp_hi | std_ulogic_vector(31 downto 0) | |
| mtime_lo | std_ulogic_vector(31 downto 0) | |
| mtime_lo_nxt | std_ulogic_vector(32 downto 0) | |
| mtime_lo_ovfl | std_ulogic_vector(00 downto 0) | |
| mtime_hi | std_ulogic_vector(31 downto 0) | |
| cmp_lo | std_ulogic | comparator and IRQ trigger -- |
| cmp_lo_ff | std_ulogic | |
| cmp_hi | std_ulogic | |
| cmp_match_ff | std_ulogic |
Constants
| Name | Type | Value | Description |
|---|---|---|---|
| hi_abb_c | natural | index_size_f(io_size_c)-1 | high address boundary bit |
| lo_abb_c | natural | index_size_f(mtime_size_c) | low address boundary bit |
Processes
- wr_access: ( clk_i )
Description
Write Access --------------------------------------------------------------------------- -------------------------------------------------------------------------------------------
- rd_access: ( clk_i )
Description
Read Access ---------------------------------------------------------------------------- -------------------------------------------------------------------------------------------
- cmp_sync: ( clk_i )
Description
Comparator ----------------------------------------------------------------------------- -------------------------------------------------------------------------------------------