Added a few more demos and one last attempt

at audio fixup. It did nothing of course lol

Reverted back to 16-bit pcm because it sounds marginally better than
8-bit

design/sd/read_data.sv

@@ -9,6 +9,7 @@
  ***/
 module read_data(
     input clk,
+    input mem_clk,
     input reset,
     input [3:0] sd_data,
     audio_buffer_interface.driver buffer

design/sd/sd_controller.sv

@@ -12,6 +12,7 @@ module sd_controller(
 (* MARK_DEBUG = "TRUE" *)
     input logic fast_clk,
     input logic crc_clk,
+    input logic mem_clk,
     input logic reset,
 (* MARK_DEBUG = "TRUE" *)
     input logic [3:0] sd_data,
@@ -104,6 +105,7 @@ read_command slowReader(
 // The data line is only ever used at fast_clk speeds
 read_data dataHandler(
     fast_clk,
+    mem_clk,
     reset,
     sd_data,
     buffer