wr2rf_vme: select noga/ga according to ga value.

e728a83e · Tristan Gingold · d82f7502 · e728a83e
Commit e728a83e authored Jun 30, 2020 by Tristan Gingold
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Showing with 4 additions and 2 deletions

wr2rf_vme.vhd hdl/top/wr2rf_vme.vhd +4 -2

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--- a/hdl/top/wr2rf_vme.vhd
+++ b/hdl/top/wr2rf_vme.vhd
@@ -729,8 +729,10 @@ begin

    vme_nogap <= not (vme_noga_n_i(0) xor vme_noga_n_i(1) xor vme_noga_n_i(2)
                      xor vme_noga_n_i(3) xor vme_noga_n_i(4));
-    vme_ga <= vme_gap_i & vme_ga_n_i when switch_n(2) = '0'
-        else vme_nogap & vme_noga_n_i; -- vme core wants low level sensitivity
+    --  Use vme_ga_n_i if not unconnected (there are pull-up).
+    --  Despite the name, the vme64x core want negated logic.
+    vme_ga <= vme_gap_i & vme_ga_n_i when vme_ga_n_i /= (4 downto 0 => '1')
+        else vme_nogap & vme_noga_n_i;

    -- VME tri-state buffers
    vme_data_b (15 downto 0)  <= vme_data_b_out    when vme_data_dir_int = '1'