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[/] [neorv32/] [trunk/] [rtl/] [core/] [neorv32_spi.vhd] - Rev 64
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-- ################################################################################################# -- # << NEORV32 - Serial Peripheral Interface Controller (SPI) >> # -- # ********************************************************************************************* # -- # Frame format: 8/16/24/32-bit receive/transmit data, always MSB first, 2 clock modes, # -- # 8 pre-scaled clocks (derived from system clock), 8 dedicated chip-select lines (low-active). # -- # Interrupt: SPI_transfer_done # -- # ********************************************************************************************* # -- # BSD 3-Clause License # -- # # -- # Copyright (c) 2021, Stephan Nolting. All rights reserved. # -- # # -- # Redistribution and use in source and binary forms, with or without modification, are # -- # permitted provided that the following conditions are met: # -- # # -- # 1. Redistributions of source code must retain the above copyright notice, this list of # -- # conditions and the following disclaimer. # -- # # -- # 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. # -- # # -- # 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. # -- # # -- # 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. # -- # ********************************************************************************************* # -- # The NEORV32 Processor - https://github.com/stnolting/neorv32 (c) Stephan Nolting # -- ################################################################################################# library ieee; use ieee.std_logic_1164.all; use ieee.numeric_std.all; library neorv32; use neorv32.neorv32_package.all; entity neorv32_spi is port ( -- host access -- 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 -- clock generator -- clkgen_en_o : out std_ulogic; -- enable clock generator clkgen_i : in std_ulogic_vector(07 downto 0); -- com lines -- spi_sck_o : out std_ulogic; -- SPI serial clock spi_sdo_o : out std_ulogic; -- controller data out, peripheral data in spi_sdi_i : in std_ulogic; -- controller data in, peripheral data out spi_csn_o : out std_ulogic_vector(07 downto 0); -- SPI CS -- interrupt -- irq_o : out std_ulogic -- transmission done interrupt ); end neorv32_spi; architecture neorv32_spi_rtl of neorv32_spi is -- IO space: module base address -- constant hi_abb_c : natural := index_size_f(io_size_c)-1; -- high address boundary bit constant lo_abb_c : natural := index_size_f(spi_size_c); -- low address boundary bit -- control reg bits -- constant ctrl_spi_cs0_c : natural := 0; -- r/w: spi CS 0 constant ctrl_spi_cs1_c : natural := 1; -- r/w: spi CS 1 constant ctrl_spi_cs2_c : natural := 2; -- r/w: spi CS 2 constant ctrl_spi_cs3_c : natural := 3; -- r/w: spi CS 3 constant ctrl_spi_cs4_c : natural := 4; -- r/w: spi CS 4 constant ctrl_spi_cs5_c : natural := 5; -- r/w: spi CS 5 constant ctrl_spi_cs6_c : natural := 6; -- r/w: spi CS 6 constant ctrl_spi_cs7_c : natural := 7; -- r/w: spi CS 7 -- constant ctrl_spi_en_c : natural := 8; -- r/w: spi enable constant ctrl_spi_cpha_c : natural := 9; -- r/w: spi clock phase constant ctrl_spi_prsc0_c : natural := 10; -- r/w: spi prescaler select bit 0 constant ctrl_spi_prsc1_c : natural := 11; -- r/w: spi prescaler select bit 1 constant ctrl_spi_prsc2_c : natural := 12; -- r/w: spi prescaler select bit 2 constant ctrl_spi_size0_c : natural := 13; -- r/w: data size (00: 8-bit, 01: 16-bit) constant ctrl_spi_size1_c : natural := 14; -- r/w: data size (10: 24-bit, 11: 32-bit) -- constant ctrl_spi_busy_c : natural := 31; -- r/-: spi transceiver is busy -- access control -- signal acc_en : std_ulogic; -- module access enable signal addr : std_ulogic_vector(31 downto 0); -- access address signal wren : std_ulogic; -- word write enable signal rden : std_ulogic; -- read enable -- accessible regs -- signal ctrl : std_ulogic_vector(14 downto 0); signal tx_data_reg : std_ulogic_vector(31 downto 0); signal rx_data : std_ulogic_vector(31 downto 0); -- clock generator -- signal spi_clk : std_ulogic; -- spi transceiver -- signal spi_start : std_ulogic; signal spi_busy : std_ulogic; signal spi_state0 : std_ulogic; signal spi_state1 : std_ulogic; signal spi_rtx_sreg : std_ulogic_vector(31 downto 0); signal spi_rx_data : std_ulogic_vector(31 downto 0); signal spi_bitcnt : std_ulogic_vector(05 downto 0); signal spi_bitcnt_max : std_ulogic_vector(05 downto 0); signal spi_sdi_ff0 : std_ulogic; signal spi_sdi_ff1 : std_ulogic; begin -- Access Control ------------------------------------------------------------------------- -- ------------------------------------------------------------------------------------------- acc_en <= '1' when (addr_i(hi_abb_c downto lo_abb_c) = spi_base_c(hi_abb_c downto lo_abb_c)) else '0'; addr <= spi_base_c(31 downto lo_abb_c) & addr_i(lo_abb_c-1 downto 2) & "00"; -- word aligned wren <= acc_en and wren_i; rden <= acc_en and rden_i; -- Read/Write Access ---------------------------------------------------------------------- -- ------------------------------------------------------------------------------------------- rw_access: process(clk_i) begin if rising_edge(clk_i) then ack_o <= acc_en and (rden_i or wren_i); -- write access -- spi_start <= '0'; if (wren = '1') then if (addr = spi_ctrl_addr_c) then -- control ctrl <= data_i(ctrl'left downto 0); end if; if (addr = spi_rtx_addr_c) then -- tx data tx_data_reg <= data_i; spi_start <= '1'; end if; end if; -- read access -- data_o <= (others => '0'); if (rden = '1') then if (addr = spi_ctrl_addr_c) then data_o(ctrl_spi_cs0_c) <= ctrl(ctrl_spi_cs0_c); data_o(ctrl_spi_cs1_c) <= ctrl(ctrl_spi_cs1_c); data_o(ctrl_spi_cs2_c) <= ctrl(ctrl_spi_cs2_c); data_o(ctrl_spi_cs3_c) <= ctrl(ctrl_spi_cs3_c); data_o(ctrl_spi_cs4_c) <= ctrl(ctrl_spi_cs4_c); data_o(ctrl_spi_cs5_c) <= ctrl(ctrl_spi_cs5_c); data_o(ctrl_spi_cs6_c) <= ctrl(ctrl_spi_cs6_c); data_o(ctrl_spi_cs7_c) <= ctrl(ctrl_spi_cs7_c); -- data_o(ctrl_spi_en_c) <= ctrl(ctrl_spi_en_c); data_o(ctrl_spi_cpha_c) <= ctrl(ctrl_spi_cpha_c); data_o(ctrl_spi_prsc0_c) <= ctrl(ctrl_spi_prsc0_c); data_o(ctrl_spi_prsc1_c) <= ctrl(ctrl_spi_prsc1_c); data_o(ctrl_spi_prsc2_c) <= ctrl(ctrl_spi_prsc2_c); data_o(ctrl_spi_size0_c) <= ctrl(ctrl_spi_size0_c); data_o(ctrl_spi_size1_c) <= ctrl(ctrl_spi_size1_c); -- data_o(ctrl_spi_busy_c) <= spi_busy; else -- spi_rtx_addr_c data_o <= rx_data; end if; end if; end if; end process rw_access; -- direct chip-select (CS) (output is low-active) -- spi_csn_o(7 downto 0) <= not ctrl(ctrl_spi_cs7_c downto ctrl_spi_cs0_c); -- Clock Selection ------------------------------------------------------------------------ -- ------------------------------------------------------------------------------------------- -- clock generator enable -- clkgen_en_o <= ctrl(ctrl_spi_en_c); -- spi clock select -- spi_clk <= clkgen_i(to_integer(unsigned(ctrl(ctrl_spi_prsc2_c downto ctrl_spi_prsc0_c)))); -- SPI Transceiver ------------------------------------------------------------------------ -- ------------------------------------------------------------------------------------------- spi_rtx_unit: process(clk_i) begin if rising_edge(clk_i) then -- input (sdi) synchronizer -- spi_sdi_ff0 <= spi_sdi_i; spi_sdi_ff1 <= spi_sdi_ff0; -- serial engine -- irq_o <= '0'; if (spi_state0 = '0') or (ctrl(ctrl_spi_en_c) = '0') then -- idle or disabled -- -------------------------------------------------------------- spi_bitcnt <= (others => '0'); spi_state1 <= '0'; spi_sdo_o <= '0'; spi_sck_o <= '0'; if (ctrl(ctrl_spi_en_c) = '0') then -- disabled spi_busy <= '0'; elsif (spi_start = '1') then -- start new transmission spi_rtx_sreg <= tx_data_reg; spi_busy <= '1'; end if; spi_state0 <= spi_busy and spi_clk; -- start with next new clock pulse else -- transmission in progress -- -------------------------------------------------------------- if (spi_state1 = '0') then -- first half of transmission -- -------------------------------------------------------------- spi_sck_o <= ctrl(ctrl_spi_cpha_c); case ctrl(ctrl_spi_size1_c downto ctrl_spi_size0_c) is when "00" => spi_sdo_o <= spi_rtx_sreg(07); -- 8-bit mode when "01" => spi_sdo_o <= spi_rtx_sreg(15); -- 16-bit mode when "10" => spi_sdo_o <= spi_rtx_sreg(23); -- 24-bit mode when others => spi_sdo_o <= spi_rtx_sreg(31); -- 32-bit mode end case; if (spi_clk = '1') then spi_state1 <= '1'; if (ctrl(ctrl_spi_cpha_c) = '0') then spi_rtx_sreg <= spi_rtx_sreg(30 downto 0) & spi_sdi_ff1; end if; spi_bitcnt <= std_ulogic_vector(unsigned(spi_bitcnt) + 1); end if; else -- second half of transmission -- -------------------------------------------------------------- spi_sck_o <= not ctrl(ctrl_spi_cpha_c); if (spi_clk = '1') then spi_state1 <= '0'; if (ctrl(ctrl_spi_cpha_c) = '1') then spi_rtx_sreg <= spi_rtx_sreg(30 downto 0) & spi_sdi_ff1; end if; if (spi_bitcnt = spi_bitcnt_max) then spi_state0 <= '0'; spi_busy <= '0'; irq_o <= '1'; end if; end if; end if; end if; end if; end process spi_rtx_unit; -- RTX Data size ------------------------------------------------------------------------ -- ------------------------------------------------------------------------------------------- data_size: process(ctrl) begin case ctrl(ctrl_spi_size1_c downto ctrl_spi_size0_c) is when "00" => spi_bitcnt_max <= "001000"; -- 8-bit mode when "01" => spi_bitcnt_max <= "010000"; -- 16-bit mode when "10" => spi_bitcnt_max <= "011000"; -- 24-bit mode when others => spi_bitcnt_max <= "100000"; -- 32-bit mode end case; end process data_size; -- RX-Data Masking ------------------------------------------------------------------------ -- ------------------------------------------------------------------------------------------- rx_mapping: process(ctrl, spi_rtx_sreg) begin case ctrl(ctrl_spi_size1_c downto ctrl_spi_size0_c) is when "00" => rx_data <= x"000000" & spi_rtx_sreg(07 downto 0); -- 8-bit mode when "01" => rx_data <= x"0000" & spi_rtx_sreg(15 downto 0); -- 16-bit mode when "10" => rx_data <= x"00" & spi_rtx_sreg(23 downto 0); -- 24-bit mode when others => rx_data <= spi_rtx_sreg(31 downto 0); -- 32-bit mode end case; end process rx_mapping; end neorv32_spi_rtl;
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