Commit 2d7930f8 authored by Tristan Gingold's avatar Tristan Gingold

vme_bus.vhd: handle fast dtack reaction (for ASYNC_DTACK)

If g_ASYNC_DTACK is set to true (the default is false), /DTACK is
asynchronously driven by /DS.  In that case, the release of /DTACK
must be read from the async driver to handle fast changes.
parent 8e083d62
......@@ -691,7 +691,10 @@ begin
-- Once the responding Slave has driven DTACK* or BERR* low, it
-- MUST NOT release them or drive DTACK* high until it detects
-- both DS0* and DS1* high.
if vme_ds_n_i = "11" then
if vme_ds_n_i = "11"
and vme_dtack_async_ctrl = '1' and vme_dtack_n_out = '0')
vme_berr_n_o <= '1';
-- Rescind DTACK.
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment