From b915c398011d6b5349046a792494d3a93b971ac8 Mon Sep 17 00:00:00 2001
From: Jens Ahrensfeld <jens@jayfield.org>
Date: Sun, 3 Mar 2019 08:39:07 +0000
Subject: [PATCH] - UART takes baudrate on init - UART calculate optimized baud
 prescaler

git-svn-id: http://moon:8086/svn/projects/HendiControl@47 fda53097-d464-4ada-af97-ba876c37ca34
---
 Control/firmware/uart_echo/main.c          |  15 +--
 Control/firmware/uart_echo/uart.c          |  24 +++-
 Control/firmware/uart_echo/uart.h          |   6 +-
 Control/firmware/uart_echo/uart_echo.cproj | 143 +++++++++++----------
 4 files changed, 104 insertions(+), 84 deletions(-)

diff --git a/Control/firmware/uart_echo/main.c b/Control/firmware/uart_echo/main.c
index d3d1e0a..52af4e0 100755
--- a/Control/firmware/uart_echo/main.c
+++ b/Control/firmware/uart_echo/main.c
@@ -13,6 +13,7 @@
 #include <avr/wdt.h>
 #include <avr/interrupt.h>
 
+#include "machine.h"
 #include "fifo.h"
 #include "message.h"
 #include "adc.h"
@@ -23,16 +24,8 @@
 #include "mcp42x6.h"
 
 #define PRINT(a,...)	printf(a, ##__VA_ARGS__)
-#define ARDUINO_NANO			1
-
-#define PRINT_PROMPT			putchar(0x0D);putchar(0x0A);putchar(':');
-#if ARDUINO_NANO
-#define F_CPU			(16000000UL)	// MHz
-#else
-#define F_CPU			(18432000UL)	// MHz
-#endif
-#define USART_BAUDRATE	9600UL
-#define BAUD_PRESCALE	(((F_CPU / (USART_BAUDRATE * 16UL))) - 1)
+#define PRINT_PROMPT	putchar(0x0D);putchar(0x0A);putchar(':');
+#define USART_BAUDRATE	115200UL
 #define TIMER_HW_CLOCK	(F_CPU/8)
 #define TIMER_IRQ_CLOCK	1000UL
 #define TIMER_HW_RELOAD	(0xFFFF-(TIMER_HW_CLOCK/TIMER_IRQ_CLOCK))
@@ -96,7 +89,7 @@ int main(void)
 	fifo_init(&messageFifo, 8, sizeof(Msg_t), "Fifo");
 	
     /* Replace with your application code */
-	uart_init(&messageFifo, BAUD_PRESCALE);
+	uart_init(&messageFifo, USART_BAUDRATE);
 	timer_init(&messageFifo, TIMER_HW_RELOAD, TimerClockSel_PS_8);
 	adc_init(&messageFifo);
 	i2c_init();
diff --git a/Control/firmware/uart_echo/uart.c b/Control/firmware/uart_echo/uart.c
index 898ec05..99467ff 100644
--- a/Control/firmware/uart_echo/uart.c
+++ b/Control/firmware/uart_echo/uart.c
@@ -33,13 +33,31 @@ ISR(USART_RX_vect)
 	}
 }
 
-void uart_init(Fifo *pFifo, uint16_t BAUD_PRESCALE)
+void uart_init(Fifo *pFifo, uint32_t baudrate)
 {
 	g_pFifo = pFifo;
 
+	uint16_t prescale8 = UART_PRESCALE(baudrate, 8UL);
+	uint16_t prescale16 = UART_PRESCALE(baudrate, 16UL);
+	
+	uint32_t baud8 = ((prescale8+1) * 8);
+	uint32_t baud16 = ((prescale16+1) * 16);
+	
+	uint32_t err8 = abs(baudrate - baud8);
+	uint32_t err16 = abs(baudrate - baud16);
+	
+	uint16_t prescale = prescale16;
+	if (err8 < err16)
+	{
+		prescale = prescale8;
+		
+		// Double UART speed
+		UCSR0A |= 1 << U2X0;
+	}
+	
 	// Set baud rate
-	UBRR0L  = (uint8_t)BAUD_PRESCALE;
-	UBRR0H = (uint8_t)(BAUD_PRESCALE >> 8);
+	UBRR0L  = (uint8_t)prescale;
+	UBRR0H = (uint8_t)(prescale >> 8);
 	
 	// Enable receiver and transmitter
 	UCSR0B = (1<<TXEN0)|(1<<RXEN0);
diff --git a/Control/firmware/uart_echo/uart.h b/Control/firmware/uart_echo/uart.h
index a3df42f..d5f7b6a 100644
--- a/Control/firmware/uart_echo/uart.h
+++ b/Control/firmware/uart_echo/uart.h
@@ -9,11 +9,15 @@
 #ifndef UART_H_
 #define UART_H_
 
+#include "machine.h"
 #include "fifo.h"
 
-void uart_init(Fifo *pFifo, uint16_t BAUD_PRESCALE);
+#define UART_PRESCALE(baudrate, smpPerBit) ((5+ 10*F_CPU / (baudrate*smpPerBit) - 1)/10)
+
+void uart_init(Fifo *pFifo, uint32_t baudrate);
 void uart_putc(char c);
 int uart_putchar(char c, FILE *stream);
 void uart_puts(char const *str);
 
+
 #endif /* UART_H_ */
\ No newline at end of file
diff --git a/Control/firmware/uart_echo/uart_echo.cproj b/Control/firmware/uart_echo/uart_echo.cproj
index 6cbe77a..9c25656 100755
--- a/Control/firmware/uart_echo/uart_echo.cproj
+++ b/Control/firmware/uart_echo/uart_echo.cproj
@@ -84,80 +84,82 @@
   <PropertyGroup Condition=" '$(Configuration)' == 'Release' ">
     <ToolchainSettings>
       <AvrGcc>
-        <avrgcc.common.Device>-mmcu=atmega328p -B "%24(PackRepoDir)\atmel\ATmega_DFP\1.2.209\gcc\dev\atmega328p"</avrgcc.common.Device>
-        <avrgcc.common.outputfiles.hex>True</avrgcc.common.outputfiles.hex>
-        <avrgcc.common.outputfiles.lss>True</avrgcc.common.outputfiles.lss>
-        <avrgcc.common.outputfiles.eep>True</avrgcc.common.outputfiles.eep>
-        <avrgcc.common.outputfiles.srec>True</avrgcc.common.outputfiles.srec>
-        <avrgcc.common.outputfiles.usersignatures>False</avrgcc.common.outputfiles.usersignatures>
-        <avrgcc.compiler.general.ChangeDefaultCharTypeUnsigned>True</avrgcc.compiler.general.ChangeDefaultCharTypeUnsigned>
-        <avrgcc.compiler.general.ChangeDefaultBitFieldUnsigned>True</avrgcc.compiler.general.ChangeDefaultBitFieldUnsigned>
-        <avrgcc.compiler.symbols.DefSymbols>
-          <ListValues>
-            <Value>NDEBUG</Value>
-          </ListValues>
-        </avrgcc.compiler.symbols.DefSymbols>
-        <avrgcc.compiler.directories.IncludePaths>
-          <ListValues>
-            <Value>%24(PackRepoDir)\atmel\ATmega_DFP\1.2.209\include</Value>
-          </ListValues>
-        </avrgcc.compiler.directories.IncludePaths>
-        <avrgcc.compiler.optimization.level>Optimize for size (-Os)</avrgcc.compiler.optimization.level>
-        <avrgcc.compiler.optimization.PackStructureMembers>True</avrgcc.compiler.optimization.PackStructureMembers>
-        <avrgcc.compiler.optimization.AllocateBytesNeededForEnum>True</avrgcc.compiler.optimization.AllocateBytesNeededForEnum>
-        <avrgcc.compiler.warnings.AllWarnings>True</avrgcc.compiler.warnings.AllWarnings>
-        <avrgcc.compiler.warnings.Pedantic>True</avrgcc.compiler.warnings.Pedantic>
-        <avrgcc.linker.libraries.Libraries>
-          <ListValues>
-            <Value>libm</Value>
-          </ListValues>
-        </avrgcc.linker.libraries.Libraries>
-        <avrgcc.assembler.general.IncludePaths>
-          <ListValues>
-            <Value>%24(PackRepoDir)\atmel\ATmega_DFP\1.2.209\include</Value>
-          </ListValues>
-        </avrgcc.assembler.general.IncludePaths>
-      </AvrGcc>
+  <avrgcc.common.Device>-mmcu=atmega328p -B "%24(PackRepoDir)\atmel\ATmega_DFP\1.2.209\gcc\dev\atmega328p"</avrgcc.common.Device>
+  <avrgcc.common.outputfiles.hex>True</avrgcc.common.outputfiles.hex>
+  <avrgcc.common.outputfiles.lss>True</avrgcc.common.outputfiles.lss>
+  <avrgcc.common.outputfiles.eep>True</avrgcc.common.outputfiles.eep>
+  <avrgcc.common.outputfiles.srec>True</avrgcc.common.outputfiles.srec>
+  <avrgcc.common.outputfiles.usersignatures>False</avrgcc.common.outputfiles.usersignatures>
+  <avrgcc.compiler.general.ChangeDefaultCharTypeUnsigned>True</avrgcc.compiler.general.ChangeDefaultCharTypeUnsigned>
+  <avrgcc.compiler.general.ChangeDefaultBitFieldUnsigned>True</avrgcc.compiler.general.ChangeDefaultBitFieldUnsigned>
+  <avrgcc.compiler.symbols.DefSymbols>
+    <ListValues>
+      <Value>NDEBUG</Value>
+      <Value>ARDUINO_NANO=1</Value>
+    </ListValues>
+  </avrgcc.compiler.symbols.DefSymbols>
+  <avrgcc.compiler.directories.IncludePaths>
+    <ListValues>
+      <Value>%24(PackRepoDir)\atmel\ATmega_DFP\1.2.209\include</Value>
+    </ListValues>
+  </avrgcc.compiler.directories.IncludePaths>
+  <avrgcc.compiler.optimization.level>Optimize for size (-Os)</avrgcc.compiler.optimization.level>
+  <avrgcc.compiler.optimization.PackStructureMembers>True</avrgcc.compiler.optimization.PackStructureMembers>
+  <avrgcc.compiler.optimization.AllocateBytesNeededForEnum>True</avrgcc.compiler.optimization.AllocateBytesNeededForEnum>
+  <avrgcc.compiler.warnings.AllWarnings>True</avrgcc.compiler.warnings.AllWarnings>
+  <avrgcc.compiler.warnings.Pedantic>True</avrgcc.compiler.warnings.Pedantic>
+  <avrgcc.linker.libraries.Libraries>
+    <ListValues>
+      <Value>libm</Value>
+    </ListValues>
+  </avrgcc.linker.libraries.Libraries>
+  <avrgcc.assembler.general.IncludePaths>
+    <ListValues>
+      <Value>%24(PackRepoDir)\atmel\ATmega_DFP\1.2.209\include</Value>
+    </ListValues>
+  </avrgcc.assembler.general.IncludePaths>
+</AvrGcc>
     </ToolchainSettings>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)' == 'Debug' ">
     <ToolchainSettings>
       <AvrGcc>
-        <avrgcc.common.Device>-mmcu=atmega328p -B "%24(PackRepoDir)\atmel\ATmega_DFP\1.2.209\gcc\dev\atmega328p"</avrgcc.common.Device>
-        <avrgcc.common.outputfiles.hex>True</avrgcc.common.outputfiles.hex>
-        <avrgcc.common.outputfiles.lss>True</avrgcc.common.outputfiles.lss>
-        <avrgcc.common.outputfiles.eep>True</avrgcc.common.outputfiles.eep>
-        <avrgcc.common.outputfiles.srec>True</avrgcc.common.outputfiles.srec>
-        <avrgcc.common.outputfiles.usersignatures>False</avrgcc.common.outputfiles.usersignatures>
-        <avrgcc.compiler.general.ChangeDefaultCharTypeUnsigned>True</avrgcc.compiler.general.ChangeDefaultCharTypeUnsigned>
-        <avrgcc.compiler.general.ChangeDefaultBitFieldUnsigned>True</avrgcc.compiler.general.ChangeDefaultBitFieldUnsigned>
-        <avrgcc.compiler.symbols.DefSymbols>
-          <ListValues>
-            <Value>DEBUG</Value>
-          </ListValues>
-        </avrgcc.compiler.symbols.DefSymbols>
-        <avrgcc.compiler.directories.IncludePaths>
-          <ListValues>
-            <Value>%24(PackRepoDir)\atmel\ATmega_DFP\1.2.209\include</Value>
-          </ListValues>
-        </avrgcc.compiler.directories.IncludePaths>
-        <avrgcc.compiler.optimization.level>Optimize debugging experience (-Og)</avrgcc.compiler.optimization.level>
-        <avrgcc.compiler.optimization.PackStructureMembers>True</avrgcc.compiler.optimization.PackStructureMembers>
-        <avrgcc.compiler.optimization.AllocateBytesNeededForEnum>True</avrgcc.compiler.optimization.AllocateBytesNeededForEnum>
-        <avrgcc.compiler.optimization.DebugLevel>Default (-g2)</avrgcc.compiler.optimization.DebugLevel>
-        <avrgcc.compiler.warnings.AllWarnings>True</avrgcc.compiler.warnings.AllWarnings>
-        <avrgcc.linker.libraries.Libraries>
-          <ListValues>
-            <Value>libm</Value>
-          </ListValues>
-        </avrgcc.linker.libraries.Libraries>
-        <avrgcc.assembler.general.IncludePaths>
-          <ListValues>
-            <Value>%24(PackRepoDir)\atmel\ATmega_DFP\1.2.209\include</Value>
-          </ListValues>
-        </avrgcc.assembler.general.IncludePaths>
-        <avrgcc.assembler.debugging.DebugLevel>Default (-Wa,-g)</avrgcc.assembler.debugging.DebugLevel>
-      </AvrGcc>
+  <avrgcc.common.Device>-mmcu=atmega328p -B "%24(PackRepoDir)\atmel\ATmega_DFP\1.2.209\gcc\dev\atmega328p"</avrgcc.common.Device>
+  <avrgcc.common.outputfiles.hex>True</avrgcc.common.outputfiles.hex>
+  <avrgcc.common.outputfiles.lss>True</avrgcc.common.outputfiles.lss>
+  <avrgcc.common.outputfiles.eep>True</avrgcc.common.outputfiles.eep>
+  <avrgcc.common.outputfiles.srec>True</avrgcc.common.outputfiles.srec>
+  <avrgcc.common.outputfiles.usersignatures>False</avrgcc.common.outputfiles.usersignatures>
+  <avrgcc.compiler.general.ChangeDefaultCharTypeUnsigned>True</avrgcc.compiler.general.ChangeDefaultCharTypeUnsigned>
+  <avrgcc.compiler.general.ChangeDefaultBitFieldUnsigned>True</avrgcc.compiler.general.ChangeDefaultBitFieldUnsigned>
+  <avrgcc.compiler.symbols.DefSymbols>
+    <ListValues>
+      <Value>DEBUG</Value>
+      <Value>ARDUINO_NANO=1</Value>
+    </ListValues>
+  </avrgcc.compiler.symbols.DefSymbols>
+  <avrgcc.compiler.directories.IncludePaths>
+    <ListValues>
+      <Value>%24(PackRepoDir)\atmel\ATmega_DFP\1.2.209\include</Value>
+    </ListValues>
+  </avrgcc.compiler.directories.IncludePaths>
+  <avrgcc.compiler.optimization.level>Optimize debugging experience (-Og)</avrgcc.compiler.optimization.level>
+  <avrgcc.compiler.optimization.PackStructureMembers>True</avrgcc.compiler.optimization.PackStructureMembers>
+  <avrgcc.compiler.optimization.AllocateBytesNeededForEnum>True</avrgcc.compiler.optimization.AllocateBytesNeededForEnum>
+  <avrgcc.compiler.optimization.DebugLevel>Default (-g2)</avrgcc.compiler.optimization.DebugLevel>
+  <avrgcc.compiler.warnings.AllWarnings>True</avrgcc.compiler.warnings.AllWarnings>
+  <avrgcc.linker.libraries.Libraries>
+    <ListValues>
+      <Value>libm</Value>
+    </ListValues>
+  </avrgcc.linker.libraries.Libraries>
+  <avrgcc.assembler.general.IncludePaths>
+    <ListValues>
+      <Value>%24(PackRepoDir)\atmel\ATmega_DFP\1.2.209\include</Value>
+    </ListValues>
+  </avrgcc.assembler.general.IncludePaths>
+  <avrgcc.assembler.debugging.DebugLevel>Default (-Wa,-g)</avrgcc.assembler.debugging.DebugLevel>
+</AvrGcc>
     </ToolchainSettings>
   </PropertyGroup>
   <ItemGroup>
@@ -179,6 +181,9 @@
     <Compile Include="i2c.h">
       <SubType>compile</SubType>
     </Compile>
+    <Compile Include="machine.h">
+      <SubType>compile</SubType>
+    </Compile>
     <Compile Include="main.c">
       <SubType>compile</SubType>
     </Compile>