handle RX/TX switching and respect CCA

[fhem-stuff] / culfw / culfw-asksin-fix.diff

Index: clib/rf_asksin.c
===================================================================
--- clib/rf_asksin.c	(revision 377)
+++ clib/rf_asksin.c	(working copy)
@@ -9,15 +9,18 @@
 
 #include "rf_asksin.h"
 
+//we receive a new byte approximately every 8 ms...
+#define RX_TIMEOUT_MS 10
+
 uint8_t asksin_on = 0;
 
 const uint8_t PROGMEM ASKSIN_CFG[] = {
-     0x00, 0x07,
+     0x00, 0x01,
      0x02, 0x2e,
      0x03, 0x0d,
      0x04, 0xE9,
      0x05, 0xCA,
-     0x07, 0x0C,
+     0x07, 0x04,
      0x0B, 0x06,
      0x0D, 0x21,
      0x0E, 0x65,
@@ -26,7 +29,7 @@
      0x11, 0x93,
      0x12, 0x03,
      0x15, 0x34,
-     0x17, 0x33, // go into RX after TX, CCA; EQ3 uses 0x03
+     0x17, 0x3F, // always go into RX, CCA; EQ3 uses 0x03
      0x18, 0x18,
      0x19, 0x16,
      0x1B, 0x43,
@@ -39,6 +42,7 @@
      0x3e, 0xc3
 };
 
+static inline uint8_t read_cc1100_rxbytes(void);
 static void rf_asksin_reset_rx(void);
 
 void
@@ -68,15 +72,35 @@
 
   my_delay_ms(4);
 
-  ccRX();
+  // enable RX, but don't enable the interrupt
+  do {
+    ccStrobe(CC1100_SRX);
+  } while (cc1100_readReg(CC1100_MARCSTATE) != MARCSTATE_RX);
 }
 
+// Workaround for CC1101 Errata 3
+static inline uint8_t
+read_cc1100_rxbytes(void)
+{
+  uint8_t rxbytes, rxbytes2;
+  
+  rxbytes = cc1100_readReg(CC1100_RXBYTES);
+  while((rxbytes2 = cc1100_readReg(CC1100_RXBYTES)) != rxbytes)
+    rxbytes = rxbytes2;
+
+  return rxbytes;
+}
+
 static void
 rf_asksin_reset_rx(void)
 {
   ccStrobe( CC1100_SFRX  );
   ccStrobe( CC1100_SIDLE );
   ccStrobe( CC1100_SNOP  );
+
+  while (read_cc1100_rxbytes() & 0x7f)
+    cc1100_readReg(CC1100_RXFIFO);
+
   ccStrobe( CC1100_SRX   );
 }
 
@@ -87,13 +111,29 @@
   uint8_t dec[MAX_ASKSIN_MSG];
   uint8_t rssi;
   uint8_t l;
+  uint8_t rxfifo_cnt;
+  uint16_t timeout;
 
   if(!asksin_on)
     return;
 
-  // see if a CRC OK pkt has been arrived
-  if (bit_is_set( CC1100_IN_PORT, CC1100_IN_PIN )) {
+  // see if there is data to be read
+  while (bit_is_set( CC1100_IN_PORT, CC1100_IN_PIN )) {
+    rxfifo_cnt = read_cc1100_rxbytes();
+
+    if (rxfifo_cnt & 0x80) // Overflow
+      break;
+
+    rxfifo_cnt &= 0x7f;
+
+    // We must not read the last byte from the RX fifo while RX is in progress (Errata 1)
+    while ((rxfifo_cnt < 2) && (cc1100_readReg(CC1100_PKTSTATUS) & (1 << 3))) {
+      my_delay_ms(1);
+      rxfifo_cnt = read_cc1100_rxbytes() & 0x7f;
+    }
+
     enc[0] = cc1100_readReg( CC1100_RXFIFO ) & 0x7f; // read len
+    rxfifo_cnt--;
 
     if (enc[0] >= MAX_ASKSIN_MSG) {
       // Something went horribly wrong, out of sync?
@@ -101,6 +141,27 @@
       return;
     }
 
+    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 (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 );
     
@@ -109,12 +170,19 @@
     }
     
     rssi = cc1100_sendbyte( 0 );
-    /* LQI = */ cc1100_sendbyte( 0 );
 
     CC1100_DEASSERT;
 
-    ccStrobe( CC1100_SRX   );
+    // We must not read the last byte from the RX fifo while RX is in progress (Errata 1)
+    while (((read_cc1100_rxbytes() & 0x7f) < 2) && (cc1100_readReg(CC1100_PKTSTATUS) & (1 << 3))) {
+      my_delay_ms(1);
+    }
 
+    l = cc1100_readReg(CC1100_RXFIFO);
+
+    if (!(l & 0x80)) // CRC not ok
+      continue;
+
     dec[0] = enc[0];
     dec[1] = (~enc[1]) ^ 0x89;
     
@@ -182,7 +250,11 @@
   
   enc[l] = dec[l] ^ dec[2];
 
-  ccTX();
+  // enable TX, wait for CCA
+  while (cc1100_readReg(CC1100_MARCSTATE) != MARCSTATE_TX) {
+    ccStrobe(CC1100_STX);
+  }
+
   if (dec[2] & (1 << 4)) { // BURST-bit set?
     // According to ELV, devices get activated every 300ms, so send burst for 360ms
     for(l = 0; l < 3; l++)
@@ -209,11 +281,12 @@
       ccStrobe( CC1100_SFTX  );
       ccStrobe( CC1100_SIDLE );
       ccStrobe( CC1100_SNOP  );
-      ccStrobe( CC1100_SRX   );
   }
   
   if(asksin_on) {
-    ccRX();
+    do {
+      ccStrobe(CC1100_SRX);
+    } while (cc1100_readReg(CC1100_MARCSTATE) != MARCSTATE_RX);
   } else {
     set_txrestore();
   }