Transcript BalloonSat Mini Flight Computer

BalloonSat Mini Flight
Computer
Programming
label:
• An address, or location for the program to
jump to
• Must end in a colon
• Can be any name, but not a command
• No spaces allowed, use an underline in
place of a space
• Can’t begin with a number
PAUSE time
• Halts program execution for a number of
milliseconds (1/1,000 of a second)
• Used to prevent the program from finishing
in a fraction of a second
HIGH C.2 and LOW C.2
• Used to trigger the camera
• HIGH activates the relay which is the
camera’s new shutter switch
• Keep HIGH for about 1 second
(PAUSE 1000)
• LOW turns off the relay
(camera needs you to release the shutter)
IF PINC.3 = n label
• Monitors the Commit Pin
• Conditional jump, only occurs if condition
is true
• Prevents flight computer from recording
data until ready for launch
• n can be either a 0 or a 1
• IF PINC.3 = 0 then Commit Pin is in place
• IF PINC.3 = 1 then Commit Pin is removed
READADC i/o,Bx
• Converts analog sensor voltage to a digital
value
• Linear conversion: 0V = 0 and 5V = 255
• Specifies the I/O pin (either C.1 or C.4) to
digitize
• Specifies the RAM memory to store the
result (B0 to B27)
Write Bn, x
• Writes a variable from temporary RAM into
permanent Data Memory
• RAM variable can be B0 to B27
• Data Memory address runs from 0 to 255
READ x,Bn
• Reads data from permanent Data Memory
into temporary RAM
• Required to send the data via SERTXD
• Data Memory address runs from 0 to 255
• RAM variable can be B0 to B27
SERTXD “text”, Bn
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Writes variable from RAM to the PC
Writes text (must enclose text in quotes)
Use the PICAXE Terminal program (F8)
Set Terminal for 4800 baud
GOTO label
• Jumps program execution to the label
• Unconditional jump, happens as soon as
command is executed
FOR Bn = x TO y
• Loop control, makes program repeat itself
• Saves program memory, a short program can be
repeated many times without writing the
program many times (maximum of 255 times)
• Bn is the RAM variable that monitors how many
times the loop of code has been repeated
• x is the starting number
• y is the finishing number
NEXT
• Placed at the end of the lines of code
repeated by the FOR command
• Indicates the end of the repeated code
• Easier to read program if the lines of code
between the FOR and NEXT are indented