Update documentation and do some basic housekeeping

.gitmodules

@@ -1,7 +1,7 @@
-[submodule "opt/tools"]
-	path = opt/tools
-	url = git@github.com:madcow/drybox-tools.git
+[submodule "tools"]
+path = opt/tools
+url = git@github.com:madcow/drybox-tools.git
 
-[submodule "opt/webgui"]
-	path = opt/webgui
-	url = git@github.com:madcow/drybox-webgui.git
+[submodule "webgui"]
+path = opt/webgui
+url = git@github.com:madcow/drybox-webgui.git

Makefile

@@ -62,7 +62,7 @@ flash: $(TARGET)
 	       -c $(ASP) -p $(ARCH)  \
 	       -U lfuse:w:0xff:m     \
 	       -U hfuse:w:0x91:m     \
-	       -U flash:w:$(TARGET)
+	       -U flash:w:$<
 
 .PHONY: clean
 clean:
@@ -85,6 +85,11 @@ listen: ./opt/tools/serial-listen.py
 	$(E) "[PY3] $<"
 	$(Q) ./$<
 
+.PHONY: listen-web
+listen-web: ./opt/webgui/Makefile
+	$(E) "[MAK] $(<D)"
+	$(Q) $(MAKE) -sC $(<D)
+
 $(TMPDIRS):
 	$(E) "[DIR] $@"
 	$(Q) $(MKDIR) $@

docs/CHANGELOG.md

@@ -0,0 +1,73 @@
+## Changelog
+
+### v0.75-alpha1
+- Fix parser tail pointer semantics.
+- Improve sensor log readability and minor naming fixes.
+- Add multiple README sections and use markdown formatting.
+- Reduce RXBUF size to match parser and space out log messages.
+- Prevent redundant writes and start implementing parser timeout.
+- Fix large serial command input triggering watchdog.
+- Merge pull request #5 from madcow/parser.
+- Implement serial command parser with floating point support.
+- Merge pull request #4 from madcow/eeprom-sentinel-v2.
+- Use reference sentinel to efficiently reset dirty flags on rollover.
+- Merge pull request #3 from madcow/eeprom-testing.
+- Pass variable structure as argument for memory functions.
+- Fix possible race condition and ensure proper reset flag detection.
+- Check MCUCSR for WDRF flag only and add TODO.
+- Implement memory wear leveling algorithm.
+- Define memory manager constants and add TODO.
+- Merge pull request #2 from madcow/eeprom.
+- Dump EEPROM to ensure low level memory access is working correctly.
+- Implement raw EEPROM read and write functionality.
+- Burn EESAVE fuse to preserve EEPROM on chip erase.
+- Define basic EEPROM data structures and functions.
+- Merge pull request #1 from madcow/thermistor.
+- Implement alternate voltage divider equation.
+- Calculate average dewpoint from multiple sensor measurements.
+- Test different approach for resistance calculation.
+- Ensure math functions are named consistently.
+- Make sure dewpoint calculations are correct.
+- Split thermistor functions into separate logical units and add TODO.
+- Implement all required conversion functions.
+- Define conversion functions for TD, T and RH.
+- Update planned FREQ, ARCH, MCU and fix superfluous whitespace.
+- Define basic structure for primary state machine and update TODOs.
+- Remove executable bit from pdf files.
+- Add data sheet for ATMEGA1284P-PU.
+- Poll ADC mode bit until conversion has finished.
+- Set FAN03 to maximum duty and declutter log output.
+- Calculate temperature from thermistor resistance.
+- Set ADC gain to 6.144V and fix multiplexer channel documentation.
+- Define constants for ADC multiplexer settings and describe I2C status flags.
+- Define constants for watchdog timeout flags.
+- Initialize OCR1A to FAN02\_MIN\_DUTY and add PWM documentation.
+- Minor coding style and consistency fixes.
+- Jump to reset vector when program exceeds specified watchdog timeout.
+- Start implementing watchdog timer.
+- Make log output slightly more readable.
+- Implement ADS1115 register reading and writing.
+- Try setting variable PWM frequency with timer2.
+- Set pin for light MOSFET to low in MOS\_Init.
+- Remove invisible runtime assertions.
+- Rename module TWI to I2C and add comments.
+- Read and translate AHT20 sensor readings.
+- Move PWM and MOSFET implementations into separate module files.
+- Ensure correct naming for PWM devices.
+- Calculate PWM\_CYCLE\_TOP from F\_CPU.
+- Add more general SetMosState() and SetPwmValue() functions.
+- Configure PWM timers for 25 KHz.
+- Handle PWM on pin PD4, PD5 and PD7.
+- Start working on system initialization.
+- Add data sheets for ADS1115 and AHT20.
+- Handle I2C multiplexer channel selection.
+- Implement USART with bot RX and TX interrupts.
+- Rewrite logging system and sync state with clients.
+- Handle numeric arguments for TEMP/DEWP commands.
+- Update documentation and add USART specification.
+- Start implementing proper parser state machine.
+- Add optional project submodules 'tools' and 'webgui'.
+- Implement ring buffer and auxiliary functions.
+- Add swapfiles and bin/ to .gitignore.
+- Handle USART\_RXC interrupt.
+- Implement basic UART reading.

docs/README.md

@@ -3,7 +3,7 @@
 ### Prerequisites
 
 You must have avr-gcc and avrdude installed. To install both
-tools on a debian-based system, please run the following
+tools on a Debian-based system, please run the following
 command:
 
     apt install avr-gcc avrdude
@@ -12,35 +12,51 @@ The names for these dependencies may differ for other package
 managers and distributions. Please check the package sources
 on your system for more information.
 
+You will also need an in-circuit programmer for Atmel AVR
+controllers like the [USBasp](https://www.fischl.de/usbasp).
+If you want to send commands and receive debug output you
+must make sure to have a serial interface available at
+`/dev/ttyUSB0`.
+
 ### Build and Install
 
 Run this next command in the project root directory to
-build and install the project using an USBasp programmer:
+build and install the project:
 
     make all
 
 If there are any errors during the flashing process you
 should find more information in core.log in the bin/
 directory. See the Makefile for different settings for
-your specific build environment. To remove all build
-related auxiliary files you may run these commands:
+your specific build environment.
+
+To remove all build related auxiliary files you may run
+these commands:
 
     make clean
     make distclean
 
 You can listen on the serial debug interface using the
 command below (if you have initialized the optional
-submodules as described in the next section):
+submodules as described in the 'Setting a New Target'
+section):
 
     make listen
 
-### Temperature and Dewpoint Targets
+Alternatively you can spin up a web server on port 443
+to interface with the device using the following command.
+Make sure to read section 'Webinterface Example' for more
+information.
 
-You can use the script below to send serial commands (you
-may need to run `git submodule update --init` if the tools
+    make listen-web
+
+### Setting a New Target
+
+The script below allows you to send serial commands (you
+may need to run `git submodule update --init` if the tools/
 directory is empty):
 
-    ./opt/tools/serial-send.py <command> <args, ...>
+    ./opt/tools/serial-send.py <command> <args ...>
 
 Issue the SET command to update the target settings:
 
@@ -50,3 +66,19 @@ Settings are stored in EEPROM and are persistent until a new
 SET command is issued. Keywords are not case-sensitive. Both
 arguments may contain a decimal point followed by a sequence
 of digits.
+
+### Webinterface Example
+
+There is an example Python web server utilizing websockets you
+can check out in `opt/webgui`. It should give you a basis for
+writing a custom network bridge and integrating the device into
+your home automation system.
+
+You must generate a self-signed certificate before you run the
+server. The configuration script will take care of it:
+
+    ./opt/webgui/configure
+
+See the README file in the webgui/ directory for prerequisites
+and more information. Please be aware that development for the
+web server has paused until the core has reached version v1.0.

src/common.h

@@ -12,13 +12,13 @@
 
 #define UNUSED(s)         (void)(s)
 #define BIT(n)            (0x1U << (n))
-#define MAX(a, b)         ((a) > (b) ? (a) : (b))
 #define MIN(a, b)         ((a) < (b) ? (a) : (b))
+#define MAX(a, b)         ((a) > (b) ? (a) : (b))
 #define CLAMP(n, hi, lo)  (MIN((hi), MAX((n), (lo))))
 
-void Info(const char *fmt, ...);
-void Error(const char *fmt, ...);
-void Print(const char *fmt, ...);
+void  Info(const char *fmt, ...);
+void  Error(const char *fmt, ...);
+void  Print(const char *fmt, ...);
 
 #include <util/delay.h>
 #define Sleep(ms) _delay_ms(ms)

src/common/memory.c

@@ -62,19 +62,19 @@ void MEM_Write(mem_block_t *in)
 	WriteBlock(head, in);
 }
 
-int MEM_Read(mem_block_t *out)
+bool MEM_Read(mem_block_t *out)
 {
 	int head;
 
 	head = GetUsedBlock();
 
 	if (head < 0) { // Empty?
-		return -1;
+		return false;
 	}
 
 	ReadBlock(head, out);
 
-	return 0;
+	return true;
 }
 
 void MEM_Free(void)

src/common/memory.h

@@ -1,6 +1,8 @@
 #ifndef MAD_CORE_COMMON_MEMORY_H
 #define MAD_CORE_COMMON_MEMORY_H
 
+#include "common/types.h"
+
 typedef struct mem_block_s mem_block_t;
 
 // Important: Must reset EEPROM memory when the size of
@@ -13,7 +15,7 @@ struct mem_block_s {
 } __attribute__((packed));
 
 void  MEM_Write(mem_block_t *in);
-int   MEM_Read(mem_block_t *out);
+bool  MEM_Read(mem_block_t *out);
 void  MEM_Free(void);
 void  MEM_Dump(void);
 

src/main.c

@@ -76,17 +76,11 @@ static int Init(void)
 	WDT_Enable();
 	WDT_SetTimeoutFlag(WDT2000); // 2 seconds
 
-	// Test persistent settings from EEPROM. There must
-	// be some sanity checking before these values are
-	// used.
+	// See if there are persistent target settings
+	// stored in EEPROM and load them. Some sanity
+	// checking must be done before using those.
 
-	// mem.temp = 20.50f;
-	// mem.dewp = 10.25f;
-	// MEM_Write(&mem);
-	// MEM_Dump();
-	// MEM_Free();
-
-	if (MEM_Read(&mem) == 0) {
+	if (MEM_Read(&mem)) { // Any valid blocks found?
 		Info("Found persistent configuration in EEPROM!");
 		Info("Using targets TEMP=%.2fC, DEWP=%.2fC.",
 			mem.temp, mem.dewp);
@@ -95,6 +89,12 @@ static int Init(void)
 		dewp_target = mem.dewp;
 	}
 
+	// mem.temp = 20.50f;
+	// mem.dewp = 10.25f;
+	// MEM_Write(&mem);
+	// MEM_Dump();
+	// MEM_Free();
+
 	// There is a possiblity to use interrupt signals
 	// for I2C communication but only as one large
 	// branching routine for the whole I2C system.
@@ -103,9 +103,9 @@ static int Init(void)
 	I2C_Init();
 	PWM_Init();
 
-	MOS_Enable(MOS03); // Lights
-	// MOS_Enable(MOS01); // Peltier
-	// MOS_Disable(MOS02); // Heating
+	MOS_Enable(MOS03);      // Lights
+	// MOS_Enable(MOS01);   // Peltier
+	// MOS_Disable(MOS02);  // Heating
 
 	// Only FAN01 and FAN02 are receiving the correct
 	// frequency (25 KHz) right now. The 16-bit timer on
@@ -117,9 +117,9 @@ static int Init(void)
 	// complicated so it might be worth it to switch to
 	// something like an ATmega328PB.
 
-	PWM_SetValue(FAN01, 50); // Fan Peltier Hot side
-	PWM_SetValue(FAN02, 50); // Fan Peltier Cold Side
-	// PWM_SetValue(FAN03, 20); // Fan Heating
+	PWM_SetValue(FAN01, 50);     // Fan Peltier Hot side
+	PWM_SetValue(FAN02, 50);     // Fan Peltier Cold Side
+	// PWM_SetValue(FAN03, 20);  // Fan Heating
 
 	// The I2C_SetChannel command changes the channel
 	// setting of the PCA9546 I2C multiplexer. Any
@@ -156,7 +156,7 @@ static void Update(void)
 		}
 	}
 
-	// Get sensor values
+	// Get latest sensor values
 	FetchSensorValues();
 
 	// Handle state
@@ -179,23 +179,25 @@ static void SetTarget(float t, float td)
 	Print("\r\n");
 	Info("Updating target configuration:");
 	Info("Setting temperature to %.2fC.", t);
-	Info("Setting new dewpoint to %.2fC.", td);
+	Info("Setting dewpoint to %.2fC.", td);
 
-	if (MEM_Read(&mem) == 0) {
+	// Even with level wearing there is a finite number
+	// of EEPROM write cycles so we should always check
+	// for redundant values. This could be handled by
+	// the underlying memory implementation.
+
+	if (MEM_Read(&mem)) {
 		if (t == mem.temp && td == mem.dewp) {
 			return; // Nothing to do
 		}
 	}
 
-	mem.temp = t;
-	mem.dewp = td;
+	// Update current targets
+	mem.temp = temp_target = t;
+	mem.dewp = dewp_target = td;
 
-	// Keep in EEPROM
+	// Store in EEPROM
 	MEM_Write(&mem);
-
-	// Update state
-	temp_target = t;
-	dewp_target = td;
 }
 
 static void FetchSensorValues(void)
@@ -204,23 +206,19 @@ static void FetchSensorValues(void)
 	float t[6], rh[3], td[3];
 
 	Print("\r\n");
-	Info("Reading sensor values...");
+	Info("Fetching sensor values...");
 
 	I2C_SetChannel(AHT01);
 	I2C_AHT20_Read(&t[0], &rh[0]);
-
 	I2C_SetChannel(AHT02);
 	I2C_AHT20_Read(&t[1], &rh[1]);
-
 	I2C_SetChannel(AHT03);
 	I2C_AHT20_Read(&t[2], &rh[2]);
 
 	raw = I2C_ADS1115_ReadRaw(ADS01);
 	t[3] = SteinhartHart(Resistance(raw));
-
 	raw = I2C_ADS1115_ReadRaw(ADS02);
 	t[4] = SteinhartHart(Resistance(raw));
-
 	raw = I2C_ADS1115_ReadRaw(ADS03);
 	t[5] = SteinhartHart(Resistance(raw));
 
@@ -230,7 +228,7 @@ static void FetchSensorValues(void)
 
 	temp = (t[0] + t[1] + t[2]) / 3;
 	rhum = (rh[0] + rh[1] + rh[2]) / 3;
-	dewp = Dewpoint(temp, rhum);
+	dewp = (td[0] + td[1] + td[2]) / 3;
 
 	Info("T1=%.2fC, TD1=%.2fC, RH1=%.2f%%, NT1=%.2fC", t[0], td[0], rh[0], t[3]);
 	Info("T2=%.2fC, TD2=%.2fC, RH2=%.2f%%, NT2=%.2fC", t[1], td[1], rh[1], t[4]);