diff --git a/src/one.c b/src/one.c
index 3ff34cc..ae201b4 100644
--- a/src/one.c
+++ b/src/one.c
@@ -279,7 +279,8 @@ int ewm_one_main(int argc, char **argv) {
 
    SDL_StartTextInput();
 
-   Uint32 ticks = SDL_GetTicks();
+   uint32_t ticks = SDL_GetTicks();
+   uint32_t phase = 1;
 
    while (true) {
       if (!ewm_one_poll_event(one, window)) { // TODO Move window into one
@@ -288,20 +289,27 @@ int ewm_one_main(int argc, char **argv) {
 
       // This is very basic throttling that does bursts of CPU cycles.
 
-      if ((SDL_GetTicks() - ticks) >= (1000 / 30)) { // TODO EWM_ONE_TTY_FPS ?
-         if (!ewm_one_step_cpu(one, 1000000 / 30)) {
+      if ((SDL_GetTicks() - ticks) >= (1000 / EWM_ONE_FPS)) {
+         if (!ewm_one_step_cpu(one, EWM_ONE_CPS / EWM_ONE_FPS)) {
             break;
          }
 
-         if (one->tty->screen_dirty) {
+         if (one->tty->screen_dirty || (phase == 0) || ((phase % (EWM_ONE_FPS / 4)) == 0)) {
             SDL_SetRenderDrawColor(one->tty->renderer, 0, 0, 0, 255);
             SDL_RenderClear(one->tty->renderer);
-            ewm_tty_refresh(one->tty);
+
+            ewm_tty_refresh(one->tty, phase, EWM_ONE_FPS);
             one->tty->screen_dirty = false;
+
             SDL_RenderPresent(one->tty->renderer);
          }
 
          ticks = SDL_GetTicks();
+
+         phase += 1;
+         if (phase == EWM_ONE_FPS) {
+            phase = 0;
+         }
       }
    }
 
diff --git a/src/one.h b/src/one.h
index e479329..d583326 100644
--- a/src/one.h
+++ b/src/one.h
@@ -23,11 +23,14 @@
 #ifndef EWM_ONE_H
 #define EWM_ONE_H
 
+#include <SDL2/SDL.h>
+
 #define EWM_ONE_MODEL_APPLE1   (0)
 #define EWM_ONE_MODEL_REPLICA1 (1)
 #define EWM_ONE_MODEL_DEFAULT  (EWM_ONE_MODEL_REPLICA1)
 
-#include <SDL2/SDL.h>
+#define EWM_ONE_FPS (40)
+#define EWM_ONE_CPS (1023000)
 
 struct cpu_t;
 struct ewm_tty_t;
diff --git a/src/tty.c b/src/tty.c
index 208e107..1f7421e 100644
--- a/src/tty.c
+++ b/src/tty.c
@@ -89,11 +89,18 @@ void ewm_tty_reset(struct ewm_tty_t *tty) {
    tty->screen_dirty = true;
 }
 
-void ewm_tty_refresh(struct ewm_tty_t *tty) {
+void ewm_tty_refresh(struct ewm_tty_t *tty, uint32_t phase, uint32_t fps) {
    for (int row = 0; row < 24; row++) {
       for (int column = 0; column < 40; column++) {
          ewm_tty_render_character(tty, row, column, tty->screen_buffer[(row * EWM_ONE_TTY_COLUMNS) + column]);
       }
    }
-   ewm_tty_render_character(tty, tty->screen_cursor_row, tty->screen_cursor_column, EWM_ONE_TTY_CURSOR);
+
+   if ((phase % (fps / 4)) == 0) {
+      tty->screen_cursor_blink = !tty->screen_cursor_blink;
+   }
+
+   if (tty->screen_cursor_blink) {
+      ewm_tty_render_character(tty, tty->screen_cursor_row, tty->screen_cursor_column, EWM_ONE_TTY_CURSOR);
+   }
 }
diff --git a/src/tty.h b/src/tty.h
index 37ddc2d..129851d 100644
--- a/src/tty.h
+++ b/src/tty.h
@@ -41,12 +41,13 @@ struct ewm_tty_t {
    uint8_t screen_buffer[EWM_ONE_TTY_ROWS * EWM_ONE_TTY_COLUMNS];
    int screen_cursor_row;
    int screen_cursor_column;
+   int screen_cursor_blink;
 };
 
 struct ewm_tty_t *ewm_tty_create(SDL_Renderer *renderer);
 void ewm_tty_destroy(struct ewm_tty_t *tty);
 void ewm_tty_write(struct ewm_tty_t *tty, uint8_t v);
 void ewm_tty_reset(struct ewm_tty_t *tty);
-void ewm_tty_refresh(struct ewm_tty_t *tty);
+void ewm_tty_refresh(struct ewm_tty_t *tty, uint32_t phase, uint32_t fps);
 
 #endif // EWM_TTY_H