prep to do big tick method

core/src/computers/ram_rom/backplane.rs

@@ -47,6 +47,7 @@ impl Backplane for RamRomComputer {
             }
         }
     }
+
     fn set_read_mode(&mut self, new_mode: bool) {
         self.read_mode = new_mode;
     }

core/src/computers/rom_only/mod.rs

@@ -11,4 +11,13 @@ pub struct RomOnlyComputer {
     pub(crate) data_bus: u8,
     pub(crate) address_bus: u16,
     pub(crate) read_mode: bool,
+}
+
+impl RomOnlyComputer {
+    pub fn tick2(&mut self, address: u16, control: u8, data: u8) -> (u8) {
+        // tick the parts...
+
+        let (_, new_data) = self.rom.tick(address, data, control == 0x01);
+        new_data
+    }
 }

core/src/computers/rom_only/rom_chunks.rs

@@ -5,4 +5,4 @@ impl RomOnlyComputer {
     pub fn rom_chunks(&self, size: usize) -> Chunks<u8> {
         self.rom.chunks(size)
     }
-}
+}