Added AUXiliary I2C bus for general purpose use of I2C devices on FMC cards

ff891eec · Peter Jansweijer · 8241cb68 · ff891eec · ff891eec · ff891eec
Commit ff891eec authored Jan 21, 2021 by Peter Jansweijer
4 changed files
--- a/board/spec7/wr_spec7_pkg.vhd
+++ b/board/spec7/wr_spec7_pkg.vhd
@@ -104,6 +104,8 @@ package wr_spec7_pkg is
      sfp_los_i            : in  std_logic                                        := '0';
      eeprom_scl           : inout  std_logic;
      eeprom_sda           : inout  std_logic;
+      aux_scl              : inout  std_logic;
+      aux_sda              : inout  std_logic;
      onewire_i            : in  std_logic;
      onewire_oen_o        : out std_logic;
      uart_rxd_i           : in  std_logic;

--- a/board/spec7/wrc_board_spec7.vhd
+++ b/board/spec7/wrc_board_spec7.vhd
@@ -155,6 +155,12 @@ entity wrc_board_spec7 is
    eeprom_sda : inout std_logic;
    eeprom_scl : inout std_logic;

+    ---------------------------------------------------------------------------
+    -- I2C AUXiliary
+    ---------------------------------------------------------------------------
+    aux_sda : inout std_logic;
+    aux_scl : inout std_logic;
+
    ---------------------------------------------------------------------------
    -- Onewire interface
    ---------------------------------------------------------------------------
@@ -464,6 +470,8 @@ begin  -- architecture struct
      sfp_los_i            => sfp_los_i,
      eeprom_scl           => eeprom_scl,
      eeprom_sda           => eeprom_sda,
+      aux_scl              => aux_scl,
+      aux_sda              => aux_sda,
      onewire_i            => onewire_i,
      onewire_oen_o        => onewire_oen_o,
      uart_rxd_i           => uart_rxd_i,

--- a/board/spec7/xwrc_board_spec7.vhd
+++ b/board/spec7/xwrc_board_spec7.vhd
@@ -156,6 +156,12 @@ entity xwrc_board_spec7 is
    eeprom_sda : inout std_logic;
    eeprom_scl : inout std_logic;

+    ---------------------------------------------------------------------------
+    -- I2C AUXiliary
+    ---------------------------------------------------------------------------
+    aux_sda : inout std_logic;
+    aux_scl : inout std_logic;
+
    ---------------------------------------------------------------------------
    -- Onewire interface
    ---------------------------------------------------------------------------
@@ -336,7 +342,7 @@ architecture struct of xwrc_board_spec7 is
    (c_slave_gpio    => x"00000f00"
     );

-  constant c_num_gpio_pins : integer := 15;
+  constant c_num_gpio_pins : integer := 17;
  signal gpio_out, gpio_in, gpio_oen : std_logic_vector(c_num_gpio_pins-1 downto 0);

  component even_odd_det is
@@ -818,6 +824,12 @@ begin  -- architecture struct
  gpio_in(13) <= even_odd_n;         -- 10MHz/1PPS phase w.r.t. clk_ref_125m
  gpio_in(14) <= sync_done; 

+  -- AUXiliary I2C tri-states
+  aux_scl  <= '0' when (gpio_out(15) = '0') else 'Z';
+  gpio_in(15) <= aux_scl;
+  aux_sda  <= '0' when (gpio_out(16) = '0') else 'Z';
+  gpio_in(16) <= aux_sda;
+
  sfp_rate_select_o <= '1';

  onewire_oen_o <= onewire_en(0);

--- a/top/spec7_ref_design/spec7_wr_ref_top.vhd
+++ b/top/spec7_ref_design/spec7_wr_ref_top.vhd
@@ -589,6 +589,9 @@ AXI2WB : xwb_axi4lite_bridge
      eeprom_scl          => scl_b,
      eeprom_sda          => sda_b,

+      aux_scl             => fmc_la23_p,
+      aux_sda             => fmc_la06_p,
+
      onewire_i           => '1',  -- No onewire, Unique ID now via
      onewire_oen_o       => open, -- 24AA025EU48 (I2C Addr 1010.001x)