SPI support (slave): receive and display frames

Makefile

@@ -26,8 +26,8 @@
 #                dependent on your programmer and operating system.
 #                This settings works for my mac
 
-PROGRAMMER = avrispmkII
-PROGRAMMER_PORT = usb
+PROGRAMMER = stk500
+PROGRAMMER_PORT = /dev/ttyUSB0
 
 # This are the hardware settings for the Blinken Buttons for Beginners. There is
 # normally no need tho change these (or anything below) (if you do not change 
@@ -40,7 +40,7 @@ PROGRAMMER_PORT = usb
 
 DEVICE     = atmega168
 CLOCK      = 8000000
-OBJECTS    = main.o core/animation.o core/display.o core/random.o core/state.o flash-content/sprites.o 
+OBJECTS    = main.o core/display.o core/spi.o
 FUSES      = -Ulfuse:w:0xe2:m -Uhfuse:w:0xdf:m -Uefuse:w:0x1:m
 
 

core/display.c

@@ -35,8 +35,6 @@
 #include <avr/pgmspace.h>
 #include <string.h>
 
-#include "state.h"
-#include "../flash-content/sprites.h"
 #include "display.h"
 
 /*
@@ -188,25 +186,6 @@ display_advance_buffer(void)
   display_status |= DISPLAY_BUFFER_ADVANCE;
 }
 
-/*
- * Loads the test pattern.
- * TODO come up with a better test pattern solution!
- */
-void
-display_load_default_sequence(void)
-{
-  uint8_t default_load_buffer[8] =
-    { 0, 0, 0, 0, 0, 0, 0, 0 };
-
-  display_current_buffer = 0;
-  copy_to_buffer(predefined_sprites[DEFAULT_1], default_load_buffer);
-  display_load_sprite(default_load_buffer);
-  display_current_buffer = 1;
-  copy_to_buffer(predefined_sprites[DEFAULT_2], default_load_buffer);
-  display_load_sprite(default_load_buffer);
-  display_current_buffer = 0;
-}
-
 /*
  * Configures the column timer (Timer 0).
  * at 156.25kHz?

core/spi.c

@@ -0,0 +1,55 @@
+/**
+ * SPI support
+ */
+
+#include <avr/io.h>
+#include <avr/interrupt.h>
+#include <util/delay.h>
+
+#include "display.h"
+
+#define SS PB2
+#define MOSI PB3
+#define MISO PB4
+#define SCK PB5
+
+// Sprite buffer
+uint8_t sprite[8] = {0, 0, 0, 0, 0, 0, 0, 0};
+uint8_t i = 0;
+
+/**
+ * Initialize SPI in slave mode
+ */
+void spi_init(void)
+{
+    volatile char IOReg;
+
+    // Set MISO output
+    DDRB |= (1<<MISO);
+
+    // Enable SPI (slave) and SPI interrupts
+    SPCR = (1<<SPE) | (1<<SPIE);
+
+    // Clear SPIF bit in SPSR
+    IOReg   = SPSR;
+    IOReg   = SPDR;
+}
+
+/**
+ * SPI interrupt routine
+ */
+ISR(SPI_STC_vect)
+{
+    // Save sprite into buffer
+    sprite[i++] = SPDR;
+
+    if (i == 8) {
+        // Sprite completed
+        i = 0;
+
+        display_load_sprite(sprite);
+        display_advance_buffer();
+    }
+}
+
+

core/spi.h

@@ -0,0 +1,10 @@
+/**
+ * SPI support
+ */
+
+#ifndef SPI_H_
+#define SPI_H_
+
+void spi_init(void);
+
+#endif /* SPI_H_ */

main.c

@@ -55,14 +55,12 @@
 #include <stdlib.h>
 #include <avr/interrupt.h>
 
-// state manages the triggering of calculations
-// according to Timer 2
-#include "core/state.h"
-// animations.c contains all routines for rendering the animations from single images
-#include "core/animation.h"
 // display.c is responsible for rendering the images on the display.
 #include "core/display.h"
 
+// spi support
+#include "core/spi.h"
+
 /*
  * This is the main routine. The main routine gets executed when the ATmega powers up.
  * It initializes all components and keeps them running, by checking if one of the state
@@ -76,9 +74,14 @@ main(void)
    * CPU components first and power up only those components we need later.
    * So here we switch anything of
    */
-  power_all_disable();
-  //now start the animations
-  animation_init();
+  // TODO: This makes SPI not work...
+  //power_all_disable();
+
+  // Initialize display
+  display_init();
+
+  // Initialize SPI
+  spi_init();
 
   /*
    * now we have initialized all components and can now switch to reactive mode.
@@ -92,10 +95,6 @@ main(void)
     */
    for( ; ;)
     {
-     /*
-      * by state_process we check if a new image has to be loaded and call the load routine
-      */
-      state_process();
     }
 }