PICs

PIC stands for peripheral interface controller. It is a type of microcontroller - that is, a computer chip that has been programmed to respond to inputs in preset ways. Essentially a PIC is a mini-computer, complete with memory, on a single chip.

PICs are used in a wide range of applications, including:

• cellular phones
• car-control systems
• burglar alarms
• microwave ovens, and
• DVD systems

There are two types of PIC chips.

• Flash PIC chips can be programmed time and time again. Flash types have an F in their codes - for example 16F84. You may have used 16F84 chips in school.
• One-time programmable (OTP) chips can be programmed once only. OTP types have a C in their code numbers eg 16C54JW

PIC component functions

Diagram of a microcontroller

• Clock and timing orchestrates the processors and the program sequences when the PIC program is running.
• Power is required to run the chip.
• Processor fetches and carries the instructions from the program and sends them to their correct locations.
• ROM (read-only memory) stores the information programmed into the chip.
• Reset will start the program at the beginning again, if required.
• Control store controls the stored program.

Programming PICs

PIC chips are programmed using computers. Most PIC programs can be represented by a flow chart [flow chart: a graphic outline of the sequence of operations needed to complete a task ] which sets out the required logic sequence.

Once completed the program is downloaded to the chip using a chip holder and cable connected to one of the computer printer ports. This is called blowing the data onto the chip.

Now try a Test Bite