created separate function for hex to char

Dependencies:   SDFileSystem ds3231 eeprom_Nikita mbed testUniGraphic_150217

Fork of SS_SensePOC2P0_11Dec2017_USERPID by rashmi v

Revision:
43:85a7f399cb9d
Parent:
36:00d96aa14658
--- a/bp.h	Mon Sep 11 10:02:46 2017 +0000
+++ b/bp.h	Mon Sep 11 13:09:29 2017 +0000
@@ -14,7 +14,7 @@
 #define PPG_SPLS BUFFER*PPG_LOOP
 #define BPLEN_BYT 10778 // TOTAL length in BYTEs for BP inclu Should change if BUffer is changed
 
-void bp(int32_t pid);
+void bp(uint32_t pid);
 uint16_t sd_BP_ECGMAX(int32_t pid); // updated- Suhasini-21/7/17
 uint16_t sd_BP_PPGMAX(int32_t pid); // updated- Suhasini-21/7/17