* Add support for ext2 filesystems and image timestamps to TQM5200 board

[karo-tx-uboot.git] / board / trab / tsc2000.c

diff --git a/board/trab/tsc2000.c b/board/trab/tsc2000.c
index df2d87f5c23e6ecf581461a7db2664f71cec6575..ca6868212eadb9a4ea45c3513602029b61ac1daa 100644 (file)
--- a/board/trab/tsc2000.c
+++ b/board/trab/tsc2000.c
@@ -31,6 +31,16 @@
 
 #include "Pt1000_temp_data.h"
 
+/* helper function */
+#define abs(value) (((value) < 0) ? ((value)*-1) : (value))
+
+/*
+ * Maximal allowed deviation between two immediate meassurments of an analog
+ * thermo channel. 1 DIGIT = 0.0276 °C. This is used to filter sporadic
+ * "jumps" in measurment.
+ */
+#define MAX_DEVIATION  18      /* unit: DIGITs of adc; 18 DIGIT = 0.5 °C */
+
 void spi_init(void)
 {
        S3C24X0_GPIO * const gpio = S3C24X0_GetBase_GPIO();
@@ -227,15 +237,48 @@ s32 tsc2000_contact_temp (void)
        long adc_pt1000, offset;
        long u_pt1000;
        long contact_temp;
-
+       long temp1, temp2;
 
        tsc2000_reg_init ();
        tsc2000_set_range (3);
 
-       adc_pt1000 = tsc2000_read_channel (14);
+       /*
+        * Because of sporadic "jumps" in the measured adc values every
+        * channel is read two times. If there is a significant difference
+        * between the two measurements, then print an error and do a third
+        * measurement, because it is very unlikely that a successive third
+        * measurement goes also wrong.
+        */
+       temp1 = tsc2000_read_channel (14);
+       temp2 = tsc2000_read_channel (14);
+       if (abs(temp2 - temp1) < MAX_DEVIATION)
+               adc_pt1000 = temp2;
+       else {
+               printf ("%s: read adc value (channel 14) exceeded max allowed "
+                       "deviation: %d * 0.0276 °C\n",
+                       __FUNCTION__, MAX_DEVIATION);
+               printf ("adc value 1: %ld DIGITs\nadc value 2: %ld DIGITs\n",
+                       temp1, temp2);
+               adc_pt1000 = tsc2000_read_channel (14);
+               printf ("use (third read) adc value: adc_pt1000 = "
+                       "%ld DIGITs\n", adc_pt1000);
+       }
        debug ("read channel 14 (pt1000 adc value): %ld\n", adc_pt1000);
 
-       offset = tsc2000_read_channel (15);
+       temp1 = tsc2000_read_channel (15);
+       temp2 = tsc2000_read_channel (15);
+       if (abs(temp2 - temp1) < MAX_DEVIATION)
+               offset = temp2;
+       else {
+               printf ("%s: read adc value (channel 15) exceeded max allowed "
+                       "deviation: %d * 0.0276 °C\n",
+                       __FUNCTION__, MAX_DEVIATION);
+               printf ("adc value 1: %ld DIGITs\nadc value 2: %ld DIGITs\n",
+                       temp1, temp2);
+               offset = tsc2000_read_channel (15);
+               printf ("use (third read) adc value: offset = %ld DIGITs\n",
+                       offset);
+       }
        debug ("read channel 15 (offset): %ld\n", offset);
 
        /*