The RPN calculator now uses key interrupts rather than polling. Close #25.

firmware/applist.h

@@ -28,7 +28,9 @@ static struct app apps[]={
   {.name="timer", .init=stopwatch_init, .draw=stopwatch_draw, .exit=stopwatch_exit},
 
   //RPN Calculator
-  {.name="rpn calc", .init=rpn_init, .draw=rpn_draw, .exit=rpn_exit},
+  {.name="rpn calc", .init=rpn_init, .draw=rpn_draw, .exit=rpn_exit,
+   .keypress=rpn_keypress
+  },
   //Hex Viewer.
   {.name="memory", .init=hex_init, .draw=hex_draw, .exit=hex_exit},
   // Diceware - passphrase generator

firmware/apps.c

@@ -115,3 +115,11 @@ void app_packetrx(uint8_t *packet, int len){
 
   apps[appindex].packetrx(packet,len);
 }
+
+//! Handles a keypress, if a handler is registered.
+void app_keypress(char ch){
+  /* We only pass it to applications that have a handler.
+   */
+  if(apps[appindex].keypress)
+    apps[appindex].keypress(ch);
+}

firmware/apps.h

@@ -16,6 +16,16 @@ struct app {
    */
   int (*exit)(void);
 
+  /* I/O can work either by interrupts or by polling.  The current
+     convention is to call getchar() to poll during the rendering loop
+     if you are checking to see if a button is held down, but to take
+     this interrupt callback when taking number entry, such as in the
+     calculator.
+     
+     Called once per unique keypress.
+  */
+  void (*keypress)(char ch);//A keypress has arrived.
+
   /* Callbacks for packets being sent and received.  Set to null if unused. */
   void (*packetrx)(uint8_t *packet, int len); //A packet has arrived.
   void (*packettx)(void); //A packet has been sent.
@@ -34,3 +44,6 @@ void app_cleartimer();
 void app_forcehome();
 //! Provide an incoming packet.
 void app_packetrx(uint8_t *packet, int len);
+
+//! Handles a keypress, if a handler is registered.
+void app_keypress(char ch);

firmware/apps/rpn.c

@@ -100,56 +100,56 @@ int rpn_exit(){
 
 //! Draws the RPN calculator.
 void rpn_draw(){
-  unsigned long i, j;
-  char ch=getchar();
-
-  //Do nothing unless a key has been pressed.
-  if(oldch!=ch)
-    lcd_zero();
-  
-  //Handle key input only when first pressed.
-  if(oldch==0){
-    //Operators
-    switch(ch){
-    case '=':
-      if(bufferdirty)
-	rpn_pushbuffer();
-      else
-	rpn_push(rpn_peek());
-      break;
-    case '.':
-      //What should this do?
-      //It's out only free button.
-      break;
-    case '+':
-      rpn_pushbuffer();
-      rpn_push(rpn_pop()+rpn_pop());
-      break;
-    case '-':
-      rpn_pushbuffer();
-      j=rpn_pop();
-      i=rpn_pop();
-      rpn_push(i-j);
-      break;
-    case '*':
-      rpn_pushbuffer();
-      rpn_push(rpn_pop()*rpn_pop());
-      break;
-    case '/':
-      rpn_pushbuffer();
-      j=rpn_pop();
-      i=rpn_pop();
-      rpn_push(i/j);
-      break;
-    }
-
-    /* Numbers are special.  They modify a buffer, and the buffer is
-       pushed onto the stack before an operator or when = is pressed.
-     */
-    if(ch>='0' && ch<='9')
-      rpn_updatebuffer(ch&0xf);
-  }
-  
-  oldch=ch;
+  //We just draw the stack.  All input comes from they keypress
+  //callback.
   rpn_drawstack();
 }
+
+//! A button has been pressed for the calculator.
+void rpn_keypress(char ch){
+  unsigned long i, j;
+
+  //Do nothing on a keyup event.
+  if(!ch)
+    return;
+  
+  //Operators
+  switch(ch){
+  case '=':
+    if(bufferdirty)
+      rpn_pushbuffer();
+    else
+      rpn_push(rpn_peek());
+    break;
+  case '.':
+    //What should this do?
+    //It's out only free button.
+    break;
+  case '+':
+    rpn_pushbuffer();
+    rpn_push(rpn_pop()+rpn_pop());
+    break;
+  case '-':
+    rpn_pushbuffer();
+    j=rpn_pop();
+    i=rpn_pop();
+    rpn_push(i-j);
+    break;
+  case '*':
+    rpn_pushbuffer();
+    rpn_push(rpn_pop()*rpn_pop());
+    break;
+  case '/':
+    rpn_pushbuffer();
+    j=rpn_pop();
+    i=rpn_pop();
+    rpn_push(i/j);
+    break;
+  }
+  
+  /* Numbers are special.  They modify a buffer, and the buffer is
+     pushed onto the stack before an operator or when = is pressed.
+  */
+  if(ch>='0' && ch<='9')
+    rpn_updatebuffer(ch&0xf);
+}

firmware/apps/rpn.h

@@ -8,3 +8,6 @@ void rpn_init();
 void rpn_draw();
 //! Clears the stack to zero, or moves to the next app if already zero.
 int rpn_exit();
+
+//! A button has been pressed for the calculator.
+void rpn_keypress(char ch);

firmware/keypad.c

@@ -3,6 +3,7 @@
  */
 
 #include <stdint.h>
+#include <stdio.h>
 #include <msp430.h>
 
 #include "apps.h"
@@ -25,6 +26,9 @@ void key_init(){
   P1DIR|=0x80; //P1.7 is output.
   P1REN|=0x80;
   P1OUT|=0x80;  //Output high.
+
+  //Trigger interrupts for keypresses so we needn't scan.
+  P2IE|=BIT2|BIT1|BIT0;
 }
 
 //! Quickly checks to see if a key is pressed.
@@ -132,7 +136,8 @@ unsigned int key_chr(code){
   return 00;
 }
 
-//! Gets a character as ASCII.
+
+//! Gets the currently held button as ASCII.  Don't use for typing.
 char getchar(){
   char c=key_chr(key_scan());
   if(c)
@@ -140,3 +145,19 @@ char getchar(){
     app_cleartimer();
   return c;
 }
+
+//! Interrupt handler for Port2.
+void __attribute__ ((interrupt(PORT2_VECTOR))) PORT2_ISR(void){
+  static char lastchar=0x00;
+  char newchar=key_chr(key_scan());
+
+  //Bail quickly when the key is the same.
+  if(lastchar==newchar) return;
+  lastchar=newchar;
+  app_cleartimer(); //Clear the idle timer.
+  
+  printf("PORT2 fired, got character 0x%02x.\n",
+	 newchar);
+  app_keypress(newchar);
+}
+

firmware/keypad.h

@@ -6,6 +6,6 @@
 unsigned int key_scan();
 //! Initialize the keypad GPIO pins.
 void key_init();
-//! Get the currently pressed button as a char.
+//! Gets the currently held button as ASCII.  Don't use for typing.
 char getchar();