Basic Micro Studio Syntax Manual

SERVO
Syntax
servo pin,pos{,repeat}
• Pin - is a variable, constant or expression that indicates what processor pin to use.
Commands
• Pos - is a variable, constant or expression that indicates servo position. The value used must be
signed to indicate left or right swing. Valid real world ranges are +/- 3000 with 0 being center. The
ranges will vary from servo to servo.
• Repeat - is a variable, constant or expression that is optional and specifi es how many times
a pulse is repeated before exiting the command. A repeat value of 0 is a special case and will
only wait until the high side of the pulse is fi nished before resuming normal program execution.
Supported
• BA - Supported
• BAN - Supported
• BAP - Supported
• BAP40 - Supported
Description
The SERVO commands will generate pulses to control a standard R/C hobby servo. The range is
-3000 to +3000. Most servos will run from -2200 to +2200. Center is typically 0. The command is a
blocking command and will wait until the pulse is fi nished.
The repeat argument can be used to drive up to 6 servos by setting it to 0. The time it takes to update
6 SERVO commands in a row with repeat = 0 is about 18ms. This leaves time for the program to
perform additional tasks before more servo pulses need to be sent.
Notes
1. Setting the repeat argument to 0 means this servo command will output 1 pulse and continue on to
the next command without waiting for the low part of the pulse to fi nish
2. Setting the repeat argument to 1 or more will cause the SERVO command to output the pulse the
number of times value is set to. Repeat = 20 would generate 20 pulses and take 400ms.
Examples
The program below demonstrates how to update more than one servo at a time using the optional repeat
argument. Setting the fi rst repeat to 0 will allow the second SERVO command to run while the fi rst would
normally be waiting for the low side of it’s pulse to fi nish. Each servo command takes approximately 3ms
when repeat is 0 so we need a pause after them to add up to approximately 20ms total.
pos var sword
main
for pos = -500 to 500
servo p0,pos,0
servo p1,-pos,0
pause 14
next
for pos = -500 to 500
servo p0,-pos,0
servo p1,pos,0
pause 14
next
goto main
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