wb_i2c_bridge: Make FSM watchdog setup more generic

This is done by adding a generic to the entity, which is connected directly to the gc_fsm_watchdog component instantiated within the wb_i2c_bridge. The user should calculate the appropriate watchdog timeout value and set it via this generic. The instantiation template in the wishbone_pkg is also updated. Signed-off-by: Theodor Stana <t.stana@cern.ch>

wb_i2c_bridge: Make FSM watchdog setup more generic
This is done by adding a generic to the entity, which is connected directly to the gc_fsm_watchdog component instantiated within the wb_i2c_bridge. The user should calculate the appropriate watchdog timeout value and set it via this generic. The instantiation template in the wishbone_pkg is also updated. Signed-off-by: Theodor Stana <t.stana@cern.ch>
159e5a99 · Theodor-Adrian Stana · 41ba89b8 · 159e5a99 · 159e5a99
Commit 159e5a99 authored Mar 28, 2014 by Theodor-Adrian Stana
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Showing with 13 additions and 11 deletions

wb_i2c_bridge.vhd modules/wishbone/wb_i2c_bridge/wb_i2c_bridge.vhd +7 -11

wishbone_pkg.vhd modules/wishbone/wishbone_pkg.vhd +6 -0

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--- a/modules/wishbone/wb_i2c_bridge/wb_i2c_bridge.vhd
+++ b/modules/wishbone/wb_i2c_bridge/wb_i2c_bridge.vhd
@@ -59,6 +59,12 @@ use ieee.numeric_std.all;
 use work.gencores_pkg.all;

 entity wb_i2c_bridge is
+  generic
+  (
+    -- FSM watchdog timeout, see Appendix A in the component documentation for
+    -- an example of setting this generic
+    g_fsm_wdt : positive
+  );
  port
  (
    -- Clock, reset
@@ -391,20 +397,10 @@ begin
  --============================================================================
  -- FSM watchdog timer
  --============================================================================
-  -- * in the case of writemregs command, a maximum of 35 bytes can be written
-  --     - 1 I2C address byte
-  --     - 2 register (Wishbone) address bytes
-  --     - 8*4 Wishbone register values
-  -- * we will therefore set the watchdog max. value to allow for 36 bytes to
-  -- be sent, considering a maximum clk_i frequency of 20 MHz (period = 50 ns)
-  -- and an SCL frequency of 100 kHz
-  -- * 100 us / 50 ns = 2000 clock cycles to send one byte
-  -- * 2000 * 36 bytes = 72000 clock cycles to send 36 bytes
-  -- * g_wdt_max = 72000
  cmp_watchdog : gc_fsm_watchdog
    generic map
    (
-      g_wdt_max => 72000
+      g_wdt_max => g_fsm_wdt
    )
    port map
    (

--- a/modules/wishbone/wishbone_pkg.vhd
+++ b/modules/wishbone/wishbone_pkg.vhd
@@ -903,6 +903,12 @@ package wishbone_pkg is
  -- I2C to Wishbone bridge, following protocol defined with ELMA
  -----------------------------------------------------------------------------
  component wb_i2c_bridge is
+    generic
+    (
+      -- FSM watchdog timeout, see Appendix A in the component documentation for
+      -- an example of setting this generic
+      g_fsm_wdt : positive
+    );
    port
    (
      -- Clock, reset