Build instructions

clone my BeRTOS git repository and switch to the 'g8ecj/all' branch that merges my 1-wire and terminal emulator branches.
Use the BeRTOS wizard in the resulting branch to create a project.
wizard/bertos.py
Hit <next>
Set project name to ardmega-turbine
Hit <next>
Select BeRTOS version
Hit <next>
Select 'I have a custom board' and select 'ATMega2560'
Hit <next>
Select toolchain
Hit <next>
Make sure the 'Automatically fix dependencies' is checked
Select the following modules

drv/kbd
drv/lcd_hd44
drv/ow_ds2413
drv/ow_ds2438
drv/ser
drv/term

Hit <next>
Hit <create>
Hit <finish>

cd into this ardmega-turbine directory of the new project, delete the ardmega-turbine directory already in it and clone this repo into it using

git clone https://github.com/g8ecj/turbine.git ardmega-turbine

Two quick patches now have to be applied. The first changes the uart to operate in double speed mode for more reliable 115200 bps operation.

diff --git a/bertos/cpu/avr/drv/ser_mega.c b/bertos/cpu/avr/drv/ser_mega.c
index 6dbf886..b936b54 100644
--- a/bertos/cpu/avr/drv/ser_mega.c
+++ b/bertos/cpu/avr/drv/ser_mega.c
@@ -462,10 +462,11 @@ struct AvrSerial
 
 static uint16_t uart_period(unsigned long bps)
 {
-       uint16_t period = DIV_ROUND(CPU_FREQ / 16UL, bps) - 1;
+       uint16_t period = DIV_ROUND(CPU_FREQ / 8UL, bps) - 1;
+       UCSR0A = BV(U2X0); /* The Arduino Uno bootloader turns on U2X0 */ \
 
        #ifdef _DEBUG
-               long skew = bps - ((CPU_FREQ / 16UL) / (long)(period + 1));
+               long skew = bps - ((CPU_FREQ / 8UL) / (long)(period + 1));
                /* 8N1 is reliable within 3% skew */
                if ((unsigned long)ABS(skew) > bps / (100 / 3))
                        kprintf("Baudrate off by %ldbps\n", skew);


The other is to remove the eeprom data from the hex file output, otherwise avrdude chokes on it.
That is done by changing at around line 320 in bertos/rules.mk
from
	$$($(1)_OBJCOPY) -O ihex $$< $$@
to
	$$($(1)_OBJCOPY) -R .eeprom -O ihex $$< $$@

Move up one level and 'make' will generate the firmware in the 'images' directory.