PBASIC
Encyclopedia
PBASIC is a microcontroller
based version of BASIC created by Parallax, Inc.
The language was created to bring ease of use to the microcontroller and embedded processor world. PBASIC is used for writing code for the BASIC Stamp
microcontrollers. After the code is written it is tokenized and loaded into an EEPROM
on the microcontroller. These tokens are fetched by the microcontroller and used to generate instructions for the processor.
and the version of PBASIC that will be used. Variables and constants are usually declared first thing in a program. The DO LOOP, FOR NEXT loop, IF and ENDIF, and some standard BASIC commands are part of the language, but many commands like PULSOUT, HIGH, LOW, DEBUG, and FREQOUT are native to PBASIC and used for special purposes that are not available in traditional BASIC (such as having the Basic Stamp ring a piezo-speaker, for example).
and to that you have to select one of these commands:
you also have to select a PBASIC version.
To do that you have to select one of these commands:
An example of a program using HIGH and LOW along with the DO...LOOP
Would Be:
An example of a program using HIGH and LOW along with the FOR
NEXT loop would be:
Comments in the code are preceded by an apostrophe ('). The microcontroller ignores the rest of the line and continues to the next each time it encounters a comment. PBASIC codes can be simply a list of statements:
microcontroller uses a version of Basic similar to the version used to program the Basic Stamp I.
Microcontroller
A microcontroller is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. Program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM...
based version of BASIC created by Parallax, Inc.
Parallax, Inc. (company)
Parallax Inc. is a privately held company in Rocklin, California. Parallax Inc. designs, manufactures, and sells BASIC Stamp microcontrollers, Propeller microcontrollers, microcontroller accessories Parallax Inc. is a privately held company in Rocklin, California. Parallax Inc. designs,...
The language was created to bring ease of use to the microcontroller and embedded processor world. PBASIC is used for writing code for the BASIC Stamp
BASIC Stamp
The BASIC Stamp is a microcontroller with a small, specialized BASIC interpreter built into ROM. It is made by Parallax, Inc. and has been popular with electronics hobbyists since the early 1990s because of its low threshold of learning and ease of use due to its simple to understand BASIC...
microcontrollers. After the code is written it is tokenized and loaded into an EEPROM
EEPROM
EEPROM stands for Electrically Erasable Programmable Read-Only Memory and is a type of non-volatile memory used in computers and other electronic devices to store small amounts of data that must be saved when power is removed, e.g., calibration...
on the microcontroller. These tokens are fetched by the microcontroller and used to generate instructions for the processor.
Syntax
When starting a PBASIC file, the programmer defines the version of the BASIC StampBASIC Stamp
The BASIC Stamp is a microcontroller with a small, specialized BASIC interpreter built into ROM. It is made by Parallax, Inc. and has been popular with electronics hobbyists since the early 1990s because of its low threshold of learning and ease of use due to its simple to understand BASIC...
and the version of PBASIC that will be used. Variables and constants are usually declared first thing in a program. The DO LOOP, FOR NEXT loop, IF and ENDIF, and some standard BASIC commands are part of the language, but many commands like PULSOUT, HIGH, LOW, DEBUG, and FREQOUT are native to PBASIC and used for special purposes that are not available in traditional BASIC (such as having the Basic Stamp ring a piezo-speaker, for example).
Programming
In PBASIC you have to select 1 of 7 different basic stamps, BS1, BS2, BS2E, BS2SX, BS2P, BS2PE, and BS2PX,and to that you have to select one of these commands:
' {$STAMP BS1}
' {$STAMP BS2}
' {$STAMP BS2e}
' {$STAMP BS2sx}
' {$STAMP BS2p}
' {$STAMP BS2pe}
' {$STAMP BS2px}
you also have to select a PBASIC version.
To do that you have to select one of these commands:
' {$PBASIC 1.0} ' use version 1.0 syntax (BS1 only)
' {$PBASIC 2.0} ' use version 2.0 syntax
' {$PBASIC 2.5} ' use version 2.5 syntax
An example of a program using HIGH and LOW along with the DO...LOOP
Would Be:
DO
HIGH 1 'turn LED in pin 1 on
PAUSE 1000 'keep it on for 1 second
LOW 1 'turn it off
PAUSE 500 'keep it off for ½ second
LOOP 'repeat forever
An example of a program using HIGH and LOW along with the FOR
NEXT loop would be:
counter VAR Byte 'sets variable "counter
FOR counter = 1 to 5
HIGH 1 'turn LED in pin 1 on
PAUSE 1000 'keep it on for 1 second
LOW 1 'turn it off
PAUSE 500 'keep it off for ½ second
NEXT 'redirects to beginning four more times
END 'end program
Comments in the code are preceded by an apostrophe ('). The microcontroller ignores the rest of the line and continues to the next each time it encounters a comment. PBASIC codes can be simply a list of statements:
HIGH 1 'turn on LED on pin 1
PAUSE 1000 'pause for one second
LOW 1 'turn off LED on pin 1
END 'end program
Other Chips
The PICAXEPICAXE
PICAXE is the name of a UK-sourced microcontroller system based on a range of Microchip PICs. There are 13 PICAXE variants of differing pin counts from 8 to 40 pins. Initially marketed for use in education and by electronics hobbyists, they are also used in commercial and technical fields,...
microcontroller uses a version of Basic similar to the version used to program the Basic Stamp I.
External links
- "Comparing PBASIC 2.5 control structures to the old PBASIC" – By Tracy Allen, EME Systems, 2003
- Parallax, Inc. – Corporate website