diff --git a/.gitignore b/.gitignore
index bbb2094..fe54891 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,4 @@
 *.o
 *.bin
 *.hex
+disasm
diff --git a/firmware/cup.c b/firmware/cup.c
index 412968f..f2c5412 100644
--- a/firmware/cup.c
+++ b/firmware/cup.c
@@ -1,6 +1,7 @@
 #include <avr/io.h>
 #include <util/delay.h>
 #include <avr/interrupt.h>
+#include <avr/pgmspace.h>
 
 #define TEMP_PIN 0
 #define IMPULS0_PIN 1
@@ -91,7 +92,7 @@ inline uint16_t linearize_temp(uint16_t temp_in)
 	uint16_t temp_out = TARGET_TEMP_MAX; //burning
 	// made from datasheet by:
 	// for i in 677 740 807 877 951 1029 1111 1196 1286 1378 1475 1575 1679 1786 1896 2003 2103 2189; do calc 5*$i/9860*65472/1.11; done
-	static const uint16_t coeffs[] =
+	static const uint16_t coeffs[] PROGMEM =
 	{
 		// in, out
 		20250, 0, // -20 celsius
@@ -117,9 +118,9 @@ inline uint16_t linearize_temp(uint16_t temp_in)
 	uint8_t i=2;
 	for (; i < (sizeof(coeffs)>>1)-2; i+=2)
 	{
-		if ( temp_in < coeffs[i] )
+		if ( temp_in < pgm_read_byte(&coeffs[i]) )
 		{
-			temp_out = (uint16_t) ( coeffs[i-1] + (uint32_t) ( (uint32_t) (temp_in-coeffs[i-2]) * (coeffs[i+1]-coeffs[i-1]) ) / (coeffs[i]-coeffs[i-2]));
+			temp_out = (uint16_t) ( pgm_read_byte(&coeffs[i-1]) + (uint32_t) ( (uint32_t) (temp_in - pgm_read_byte(&coeffs[i-2])) * (pgm_read_byte(&coeffs[i+1])-pgm_read_byte(&coeffs[i-1])) ) / (pgm_read_byte(&coeffs[i])-pgm_read_byte(&coeffs[i-2])));
 			break;
 		}
 	}