double frame buffer

1 files changed, 71 insertions, 24 deletions

diff --git a/anzeige.c b/anzeige.c
index cf83f25..cddc0a8 100644
--- a/anzeige.c
+++ b/anzeige.c
@@ -5,12 +5,15 @@
 //  Dom and Gert
 //  Revised: 15-Feb-2013
 
+#ifndef __arm__
+#define SKIP_GPIO
+#endif
 
 // Access from ARM Running Linux
 
 #define BCM2708_PERI_BASE        0x20000000
 #define GPIO_BASE                (BCM2708_PERI_BASE + 0x200000) /* GPIO controller */
-
+#define _GNU_SOURCE
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -33,6 +36,11 @@
 int  mem_fd;
 void *gpio_map;
 
+typedef struct {
+   char buf[2][35];
+   int should_buf, is_buf, keep_running;
+} t_display_data;
+
 // I/O access
 volatile unsigned *gpio;
 
@@ -53,7 +61,7 @@ volatile unsigned *gpio;
 
 void setup_io();
 void drop_privileges();
-void *put_on_display(void *content);
+void *put_on_display(void *param);
 
 void printButton(int g)
 {
@@ -66,10 +74,18 @@ void printButton(int g)
 int main(int argc, char **argv)
 {
   pthread_t thread_id;
-  char *content;
-
+  t_display_data display_data = {
+    "abcdefghijklmnopqrstuvwxyzabcdefghi",
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHI",
+    0,
+    0,
+    1
+  };
+
+#ifndef SKIP_GPIO
   // Set up gpi pointer for direct register access
-//  setup_io();
+  setup_io();
+#endif
 
   // Drop root privileges
   drop_privileges();
@@ -81,6 +97,7 @@ int main(int argc, char **argv)
   * so at least you still have your code changes written to the SD-card! *
  \************************************************************************/
 
+#ifndef SKIP_GPIO
   // must use INP_GPIO before we can use OUT_GPIO
   INP_GPIO(SER_DAT_PIN);
   OUT_GPIO(SER_DAT_PIN);
@@ -91,9 +108,20 @@ int main(int argc, char **argv)
   INP_GPIO(PAR_CLK_PIN);
   OUT_GPIO(PAR_CLK_PIN);
   INP_GPIO(SENSE_PIN);
+#endif
 
-  content = "0123456789abcdefghijklmnopqrstuvwxy";
-  pthread_create(&thread_id, NULL, put_on_display, content);
+  pthread_create(&thread_id, NULL, put_on_display, &display_data);
+
+  for (int i=0; i<20; i++) {
+     usleep(500000);
+     if (display_data.should_buf == display_data.is_buf) {
+        for (int j=0; j<35; j++)
+           display_data.buf[1-display_data.is_buf][j] -= 1;
+     }
+     display_data.should_buf ^= 0x01;
+  }
+
+  display_data.keep_running = 0;
   pthread_join(thread_id, NULL);
 
   return 0;
@@ -155,8 +183,9 @@ void drop_privileges()
 //
 // Shift the bits provided in content into the display
 //
-void *put_on_display(void *content)
+void *put_on_display(void *param)
 {
+   t_display_data *display_data = param;
    char *raw_output;
    int line;
 
@@ -165,25 +194,43 @@ void *put_on_display(void *content)
       perror("malloc failed");
       exit(-1);
    }
-   for (line=0; line<7; line++) {
-      raw_output[line*6] = 1<<line;
-      memmove(raw_output+1+6*line,((char*)content)+5*line,5);
-   }
-   while (1)
+
+   while (display_data -> keep_running) {
+
+#ifdef SKIP_GPIO
+      printf("\n");
+#endif
+      display_data -> is_buf = display_data -> should_buf;
       for (line=0; line<7; line++) {
-         GPIO_CLR = 1<<GATE_PIN; // Licht an
-         for (int byte=0; byte<6; byte++) {
-            for (int bit=0; bit<8; bit++) {
-               GPIO_CLR = 1<<SER_CLK_PIN;
-               GPIO_ALTER((*(raw_output+6*line+byte)>>bit) & 0x01) = 1<<SER_DAT_PIN;
-               GPIO_SET = 1<<SER_CLK_PIN;
+         raw_output[line*6] = 1<<line;
+         memmove(raw_output+1+6*line,&(display_data -> buf[display_data -> is_buf][5*line]),5);
+      }
+         for (line=0; line<7; line++) {
+#ifndef SKIP_GPIO
+            GPIO_CLR = 1<<GATE_PIN; // Licht an
+#endif
+            for (int byte=0; byte<6; byte++) {
+#ifndef SKIP_GPIO
+               for (int bit=0; bit<8; bit++) {
+                  GPIO_CLR = 1<<SER_CLK_PIN;
+                  GPIO_ALTER((*(raw_output+6*line+byte)>>bit) & 0x01) = 1<<SER_DAT_PIN;
+                  GPIO_SET = 1<<SER_CLK_PIN;
+               }
+#else
+               if (byte==0)
+                  printf(" %02x ", *(raw_output+6*line+byte));
+               else
+                  printf("%c", *(raw_output+6*line+byte));
+#endif
             }
+            usleep(1000);
+#ifndef SKIP_GPIO
+            GPIO_SET = 1<<GATE_PIN; // Licht aus
+            GPIO_CLR = 1<<PAR_CLK_PIN;
+            GPIO_SET = 1<<PAR_CLK_PIN;
+#endif
          }
-         usleep(1000);
-         GPIO_SET = 1<<GATE_PIN; // Licht aus
-         GPIO_CLR = 1<<PAR_CLK_PIN;
-         GPIO_SET = 1<<PAR_CLK_PIN;
-      }
+   }
    free(raw_output);
    return NULL;
 } // put_on_screen