diff --git a/Makefile b/Makefile
index 9794455..ea88ccd 100644
--- a/Makefile
+++ b/Makefile
@@ -3,7 +3,7 @@ CFLAGS = -Isaturn
 OPT ?= -Og
 LIB = ./saturn
 
-SRC = main.o
+SRC = main.o input.o
 DEP = $(patsubst %.o,%.d,$(SRC))
 
 res = $(subst pokered/,res/,$(patsubst %.$(1),%.$(1).o,$(wildcard $(2)*.$(1))))
diff --git a/input.cpp b/input.cpp
new file mode 100644
index 0000000..23d8050
--- /dev/null
+++ b/input.cpp
@@ -0,0 +1,73 @@
+#include <cstdint>
+
+#include "smpc.h"
+
+#include "input.hpp"
+#include "common/intback.hpp"
+
+constexpr int input_arr = 10;
+constexpr int input_das = 20;
+constexpr int input_debounce = 2;
+
+static inline void
+input_count(count_flop_t& button, const uint32_t input, const uint32_t mask)
+{
+  if ((input & mask) == 0) {
+    if (button.count < input_debounce)
+      button.count += 1;
+    else
+      button.das += 1;
+  } else {
+    if (button.count == 0) {
+      button.flop = 0;
+      button.das = 0;
+      button.repeat = 0;
+    }
+    else if (button.count > 0)
+      button.count -= 1;
+  }
+}
+
+static inline int32_t
+input_flopped(count_flop_t& button)
+{
+  if (button.count == input_debounce && button.flop == 0) {
+    button.flop = 1;
+    return 1;
+  } else if (button.flop == 1 && button.das == input_das && button.repeat == 0) {
+    button.repeat = 1;
+    button.das = 0;
+    return 2;
+  } else if (button.repeat == 1 && (button.das == input_arr)) {
+    button.das = 0;
+    return 2;
+  } else {
+    return 0;
+  }
+}
+
+input_t input = { 0 };
+
+void digital_callback(uint8_t fsm_state, uint8_t data)
+{
+  switch (fsm_state) {
+  case intback::DATA1:
+    input_count(input.right, data, DIGITAL__1__RIGHT);
+    input_count(input.left, data, DIGITAL__1__LEFT);
+    input_count(input.down, data, DIGITAL__1__DOWN);
+    input_count(input.up, data, DIGITAL__1__UP);
+    input_count(input.start, data, DIGITAL__1__START);
+    input_count(input.a, data, DIGITAL__1__A);
+    input_count(input.c, data, DIGITAL__1__C);
+    input_count(input.b, data, DIGITAL__1__B);
+    break;
+  case intback::DATA2:
+    input_count(input.r, data, DIGITAL__2__R);
+    input_count(input.x, data, DIGITAL__2__X);
+    input_count(input.y, data, DIGITAL__2__Y);
+    input_count(input.z, data, DIGITAL__2__Z);
+    input_count(input.l, data, DIGITAL__2__L);
+    break;
+  default: break;
+  }
+}
diff --git a/input.hpp b/input.hpp
new file mode 100644
index 0000000..c2d7574
--- /dev/null
+++ b/input.hpp
@@ -0,0 +1,30 @@
+#pragma once
+
+#include <stdint.h>
+
+struct count_flop_t {
+  int8_t count;
+  uint8_t flop;
+  uint8_t das;
+  uint8_t repeat;
+};
+
+struct input_t {
+  count_flop_t right;
+  count_flop_t left;
+  count_flop_t down;
+  count_flop_t up;
+  count_flop_t start;
+  count_flop_t a;
+  count_flop_t b;
+  count_flop_t c;
+  count_flop_t r;
+  count_flop_t x;
+  count_flop_t y;
+  count_flop_t z;
+  count_flop_t l;
+};
+
+void digital_callback(uint8_t fsm_state, uint8_t data);
+
+extern input_t input;
diff --git a/main.cpp b/main.cpp
index 586918d..782d576 100644
--- a/main.cpp
+++ b/main.cpp
@@ -1,11 +1,16 @@
 #include <cstdint>
 
 #include "vdp2.h"
+#include "scu.h"
+#include "smpc.h"
+#include "sh2.h"
 
 #include "common/copy.hpp"
 #include "common/vdp2_func.hpp"
+#include "common/intback.hpp"
 
 #include "test.cpp"
+#include "input.hpp"
 
 constexpr inline uint16_t rgb15(int32_t r, int32_t g, int32_t b)
 {
@@ -88,6 +93,25 @@ void render(const uint32_t base_pattern)
   }
 }
 
+static uint32_t base_pattern;
+
+extern "C"
+void v_blank_in_int(void) __attribute__ ((interrupt_handler));
+void v_blank_in_int()
+{
+  render(base_pattern);
+}
+
+extern "C"
+void smpc_int(void) __attribute__ ((interrupt_handler));
+void smpc_int(void)
+{
+  scu.reg.IST &= ~(IST__SMPC);
+  scu.reg.IMS = ~(IMS__SMPC | IMS__V_BLANK_IN);
+
+  intback::fsm(digital_callback, nullptr);
+}
+
 void main()
 {
   v_blank_in();
@@ -122,11 +146,6 @@ void main()
   constexpr int page_size = 64 * 64 * 2; // N0PNB__1WORD (16-bit)
   constexpr int plane_size = page_size * 1;
 
-  vdp2.reg.CYCA0 = 0xeeeeeeee;
-  vdp2.reg.CYCA1 = 0xeeeeeeee;
-  vdp2.reg.CYCB0 = 0xeeeeeeee;
-  vdp2.reg.CYCB1 = 0xeeeeeeee;
-
   vdp2.reg.MPOFN = MPOFN__N0MP(0); // bits 8~6
   vdp2.reg.MPABN0 = MPABN0__N0MPB(0) | MPABN0__N0MPA(plane_a); // bits 5~0
   vdp2.reg.MPCDN0 = MPABN0__N0MPD(0) | MPABN0__N0MPC(0); // bits 5~0
@@ -134,16 +153,26 @@ void main()
   uint32_t top = (sizeof (union vdp2_vram));
   palette_data();
   uint32_t base_address = top = cell_data(tilesets[tileset_t::overworld].tileset, top);
-  uint32_t base_pattern = base_address / 32;
+  base_pattern = base_address / 32;
 
   /* use 1-word (16-bit) pattern names */
   vdp2.reg.PNCN0 = PNCN0__N0PNB__1WORD | PNCN0__N0CNSM | PNCN0__N0SCN((base_pattern >> 10) & 0x1f);
   //vdp2.reg.PNCN0 = PNCN0__N0PNB__2WORD | PNCN0__N0CNSM;
 
-  render(base_pattern);
-
   vdp2.reg.CYCA0 = 0x0fff'ffff;
   vdp2.reg.CYCA1 = 0xffff'ffff;
   vdp2.reg.CYCB0 = 0xffff'ffff;
   vdp2.reg.CYCB1 = 0x4fff'ffff;
+
+  // initialize smpc
+  smpc.reg.DDR1 = 0; // INPUT
+  smpc.reg.DDR2 = 0; // INPUT
+  smpc.reg.IOSEL = 0; // SMPC control
+  smpc.reg.EXLE = 0; //
+
+  sh2_vec[SCU_VEC__SMPC] = (u32)(&smpc_int);
+  sh2_vec[SCU_VEC__V_BLANK_IN] = (u32)(&v_blank_in_int);
+
+  scu.reg.IST = 0;
+  scu.reg.IMS = ~(IMS__SMPC | IMS__V_BLANK_IN);
 }