How to get data from different characteristics

Question

Hello, 
 i have a BLE device running with a service with three writable characteristics. At the moment I have one data handler function.
If there is any characteristic written, the software will jump to this data handler. My question is, how can I differ, which charcteristic was written?? 
 void memory_data_handler(ble_memory_t * p_com, uint8_t * p_data, uint16_t length){
	dbg_printf("*** Mem service data written:\r");
	for (uint32_t i = 0; i < length; i++)
{
 memContent[i] = p_data[i];
 dbg_printf("data[%d] = 0x%x\r", i, memContent[i]);
}}
 
 Is there a opportunity to get a switch case into the datahandler? Or do I have to write a data_handler function for every characteristic? Then I would have to call the right data_handler function in the 
 static void on_write(ble_memory_t * p_com, ble_evt_t * p_ble_evt)
 
 function... 
 Thanks for any help! 
 Regards,
BTprogrammer

RK · Accepted Answer

All the information is in the p_ble_evt, if you follow that down you'll find the characteristic being written (and a whole load of other information). So yes you need to do something in the on_write handler to either call one of three functions or pull the information out of the structure and pass it as another argument to one function or any combination of those. 
 The current signature of your memory_data_handler() has already lost the information about which characteristic was written. 
 If your three writable characteristics are basically very similar and handled in similar ways, then use one handler and just pass it the characteristic pulled from the event, if your three characteristics are quite different and would benefit from each having its own handler code, then switch inside the on_write() and call one of three pieces of code.

How to get data from different characteristics

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