Fixed baud rate issue

Move SIGROW compensation from system-wide to UART-specific
Use the correct formula to calculate baud divider based on datasheet

Author: agdl

Diff for: cores/arduino/UART.cpp

@@ -160,9 +160,9 @@ void UartClass::begin(unsigned long baud, uint16_t config)
             error = 1;
         }
 
-        // ********Check if desired baud rate is within the acceptable range for using normal RX-mode********
-        // Condition from datasheet
-        // This limits the minimum baud_setting value to 64 (0x0040)
+    // ********Check if desired baud rate is within the acceptable range for using normal RX-mode********
+    // Condition from datasheet
+    // This limits the minimum baud_setting value to 64 (0x0040)
     } else if ((16 * baud <= F_CPU_CORRECTED)) {
 
         // Check that the desired baud rate is not so low that it will
@@ -195,6 +195,10 @@ void UartClass::begin(unsigned long baud, uint16_t config)
         digitalWrite(_hwserial_tx_pin, HIGH);
         pinMode(_hwserial_tx_pin, OUTPUT);
 
+        int8_t sigrow_val = SIGROW.OSC16ERR5V;
+        baud_setting *= (1024 + sigrow_val);
+        baud_setting /= 1024;
+
         // assign the baud_setting, a.k.a. BAUD (USART Baud Rate Register)
         (*_hwserial_module).BAUD = (int16_t) baud_setting;
 

Diff for: cores/arduino/wiring.c

@@ -313,14 +313,6 @@ void init()
 		_PROTECTED_WRITE(CLKCTRL_MCLKCTRLB, 0x00);
 	#endif
 
-
- 	#if (PERFORM_SIGROW_CORRECTION_F_CPU == 1)
- 	/* Calculate actual F_CPU with error values from signature row */
-	int8_t sigrow_val = SIGROW.OSC16ERR5V;
- 	cpu_freq *= (1024 + sigrow_val);
- 	cpu_freq /= 1024; 	
- 	#endif /* (CORRECT_F_CPU == 1) */
-
 	/* Apply calculated value to F_CPU_CORRECTED */
 	F_CPU_CORRECTED = (uint32_t)cpu_freq;