make embedded memory with program code read-only (not strictly needed, but protects it from accidental overwriting before reset button is pressed)

1 files changed, 6 insertions, 4 deletions

diff --git a/design/embedded_bram_slave.v b/design/embedded_bram_slave.v
index 17738af..3829316 100644
--- a/design/embedded_bram_slave.v
+++ b/design/embedded_bram_slave.v
@@ -30,6 +30,11 @@ module embedded_bram_slave
       if (WORDS_TO_INITIALIZE) begin
 	 initial
 	   $readmemb(INITIAL_CONTENTS_FILE, memory, 0, WORDS_TO_INITIALIZE - 1);
+      end else begin
+	 always @ (posedge CLK_I) begin
+	    if (!RST_I && STB_I && WE_I)
+	      memory[ADR_I] <= DAT_I;
+	 end
       end
    endgenerate
 
@@ -47,9 +52,6 @@ module embedded_bram_slave
 	 ack <= STB_I;
 
 	 output_data <= memory[ADR_I];
-
-	 if (STB_I && WE_I)
-	   memory[ADR_I] <= DAT_I;
       end
-   end // always @ (posedge CLK_I)
+   end
 endmodule // embedded_bram_slave