From 1bfa61a8221f20d0454347161dbc69a27e1d4cb0 Mon Sep 17 00:00:00 2001
From: Michael Gernoth <michael@gernoth.net>
Date: Fri, 21 Jun 2013 13:16:08 +0200
Subject: [PATCH] fix logic error in comparison and handle rx overflow

---
 culfw/culfw-asksin-fix.diff | 53 ++++++++++++++++++++++++-------------
 1 file changed, 34 insertions(+), 19 deletions(-)

diff --git a/culfw/culfw-asksin-fix.diff b/culfw/culfw-asksin-fix.diff
index bbe630f..2a84f89 100644
--- a/culfw/culfw-asksin-fix.diff
+++ b/culfw/culfw-asksin-fix.diff
@@ -2,8 +2,13 @@ Index: clib/rf_asksin.c
 ===================================================================
 --- clib/rf_asksin.c	(revision 373)
 +++ clib/rf_asksin.c	(working copy)
-@@ -11,13 +11,13 @@
+@@ -9,15 +9,18 @@
  
+ #include "rf_asksin.h"
+ 
++//we receive a new byte approximately every 7 ms...
++#define RX_TIMEOUT_MS 10
++
  uint8_t asksin_on = 0;
  
 -const uint8_t PROGMEM ASKSIN_CFG[50] = {
@@ -19,7 +24,7 @@ Index: clib/rf_asksin.c
       0x0B, 0x06,
       0x0D, 0x21,
       0x0E, 0x65,
-@@ -26,18 +26,22 @@
+@@ -26,18 +29,22 @@
       0x11, 0x93,
       0x12, 0x03,
       0x15, 0x34,
@@ -45,7 +50,7 @@ Index: clib/rf_asksin.c
  void
  rf_asksin_init(void)
  {
-@@ -56,20 +60,44 @@
+@@ -56,20 +63,44 @@
    my_delay_us(100);
  
    // load configuration
@@ -96,11 +101,12 @@ Index: clib/rf_asksin.c
  void
  rf_asksin_task(void)
  {
-@@ -77,18 +105,41 @@
+@@ -77,18 +108,51 @@
    uint8_t dec[MAX_ASKSIN_MSG];
    uint8_t rssi;
    uint8_t l;
 +  uint8_t rxfifo_cnt;
++  uint16_t timeout;
  
    if(!asksin_on)
      return;
@@ -128,22 +134,31 @@ Index: clib/rf_asksin.c
 +      return;
 +    }
 +
-+    l = 50;
-+    while (l-- && ((enc[0] + 2) < rxfifo_cnt)) { // Wait for more data
-+      my_delay_ms(1);
-+      rxfifo_cnt = (read_cc1100_rxbytes() & 0x7f);
-+    }
++    if ((enc[0] + 2) > rxfifo_cnt) {
++      timeout = RX_TIMEOUT_MS * ((enc[0] + 2) - rxfifo_cnt);
++      while (timeout-- && ((enc[0] + 2) > rxfifo_cnt)) { // Wait for more data
++        my_delay_ms(1);
++        rxfifo_cnt = read_cc1100_rxbytes();
 +
-+    if (!l) {
-+      // Not enough data received, out of sync?
-+      rf_asksin_reset_rx();
-+      return;
++        if (rxfifo_cnt & 0x80) { // Overflow
++          rf_asksin_reset_rx();
++          return;
++	}
++ 
++        rxfifo_cnt &= 0x7f;
++      }
++
++      if (!timeout) {
++        // Not enough data received, out of sync?
++        rf_asksin_reset_rx();
++        return;
++      }
 +    }
 +
      CC1100_ASSERT;
      cc1100_sendbyte( CC1100_READ_BURST | CC1100_RXFIFO );
      
-@@ -97,14 +148,19 @@
+@@ -97,14 +161,19 @@
      }
      
      rssi = cc1100_sendbyte( 0 );
@@ -168,7 +183,7 @@ Index: clib/rf_asksin.c
      dec[0] = enc[0];
      dec[1] = (~enc[1]) ^ 0x89;
      
-@@ -113,7 +169,6 @@
+@@ -113,7 +182,6 @@
      
      dec[l] = enc[l] ^ dec[2];
      
@@ -176,7 +191,7 @@ Index: clib/rf_asksin.c
      if (tx_report & REP_BINTIME) {
        
        DC('a');
-@@ -131,26 +186,17 @@
+@@ -131,26 +199,17 @@
        
        DNL();
      }
@@ -212,7 +227,7 @@ Index: clib/rf_asksin.c
  }
  
  void
-@@ -173,20 +219,7 @@
+@@ -173,20 +232,7 @@
      my_delay_ms(3);             // 3ms: Found by trial and error
    }
  
@@ -233,7 +248,7 @@ Index: clib/rf_asksin.c
    enc[0] = dec[0];
    enc[1] = (~dec[1]) ^ 0x89;
  
-@@ -195,6 +228,15 @@
+@@ -195,6 +241,15 @@
    
    enc[l] = dec[l] ^ dec[2];
  
@@ -249,7 +264,7 @@ Index: clib/rf_asksin.c
    // send
    CC1100_ASSERT;
    cc1100_sendbyte(CC1100_WRITE_BURST | CC1100_TXFIFO);
-@@ -205,12 +247,17 @@
+@@ -205,12 +260,17 @@
  
    CC1100_DEASSERT;
  
-- 
2.39.5