In this section we will explore how to use the Microchip PIC mostly the 16FA and the 12F While the previous section on the PIC18F was written in C . UK The translation of this manual and all other information can be found on the CD. SP La traducción de este manual de instrucciones y toda otra información . MPLAB IDE v does not have PICkit2 support for PIC16F and I . it will be much more obvious with a working example and manuals.
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A number of sequences are programmed into the firmware manuaal provide some interesting visual effects and chase sequences, including the classic effect seen on the car in the Knight Rider TV series. The software has sequential, random and manual sequence run modes and manual advance to the next sequence in any mode. The selected sequence and mode are also saved to non-volatile memory so it will always restart in the selected mode.
As well as using it as a LED chaser it is great for adding effects to toys and models. However, if you just want a cool LED chaser 16f62 having to write any code, a ready written LED chaser program including 34 chase effects with source code and programmer ready HEX files is provided at the bottom of this page.
The circuit has been constructed on a PCB but can easily be built on strip-board or a solderless breadboard. They run exactly the same base code, just use different sequences to suit the layout of the boards.
Download schematic in PDF. The program that runs mmanual this chip controls the LEDs attached to the output port pins. Resistor R9 provides a pull-up for the input connected to switch S1.
Capacitor C1 is used to decouple the 5 volt power supply to the PIC. If you’re building the circuit on a breadboard or stripboard you should ensure it is located close to the PICs Vdd connection pin Power is supplied to the circuit via J1 and must be smooth DC between 9 and 14 volts. The PIC requires a precisely controlled 5 volt supply and this is provided by IC1, a 3-terminal, 5 volt regulator.
Typical current drawn by the circuit with all LEDs on is only around mA so the voltage regulator doesn’t require any additional heatsink.
Capacitors C2 and C3 166f28 the regulator. Diode D1 protects the circuit from accidental reverse polarity of the input voltage. You can buy all the parts needed to build this project from most component suppliers world wide.
In the UK you can get 16f6288 from Rapid Online and I’ve included a parts list with their part numbers below. You should check part and descriptions are correct when ordering 1f6628 case I’ve made a mistake transferring them onto this page. Ordering parts from Rapid? Note the silver band on the body of the diode. Ensure it is fitted the correct way round so it matches the PCB overlay. Fit the three capacitors, C1, C2, C3. If manuaal assembling from the kit C1 and C3 are the same value, but can be one of two types and will be marked ”.
Fit the socket for IC2. Note the notch in one end of the socket. It maual be fitted so the notch is in the same direction maanual the marking on the PCB overlay. Now fit the voltage regulator IC1, the switch and the DC power jack.
Next fit the eight LEDs. You will see that one lead is shorter than the other. You will need to bend the leads of the LED through 90 o as shown in fig 8. It is advisable to solder only one lead of each LED. Once they are all in place you can move the LED body to get them all aligned before soldering the other leads. With the PCB assembled but without the PIC installed manul the socket, apply power to the board and check that the regulator isn’t warm.
If you have a voltmeter handy, make sure it measures a nominal 5 volts between pins 5 and 14 of the IC socket. With everything assembled and having tested the 5 volt supply, disconnect 16g628 from the board.
PIC16F – Microcontrollers and Processors – Microcontrollers and Processors
Be sure to fit it the correct way round. In fig 11 you can see a close up of the notch in one end of the PIC’s plastic body. This must be aligned with the notch in the socket. This 16ff628 show the completed LED chaser operating. The board includes a 5 volt regulator and reverse polarity protection diode on board.
You will need to use a suitable DC power supply rated between 8 and 12 volts and able to supply at least mA. In the UK you can buy a suitable power supply from Rapid Electronics.
The part number for this is included in the component listing above should you not already have something available.
Fitting into a PC case. If you plan on using this inside a PC as a case mod’ you can power it from the PC power supply. For either method if you’re taking the power from a 4 pin drive connector ensure the unused power connection can’t short manuual on anything inside the case.
Microchip PIC16F628 Assembly Code Programs Tutorial
When fitting the LED chaser PCB, make sure the bottom of the circuit board can’t short out on any metal work inside the case. If it suits your application, the circuit can be powered from batteries. You will need to omit the following parts: Without D1 there is no reverse polarity protection so ensure the battery connections are correct. When the code is running in any mode, a short press of the switch will make the controller skip to the next sequence.
To enter setup mode, press and hold the switch. Once it enters setup mode one of three LEDs will light indicating the current run mode. A short press of the switch cycles through the three maunal. When the desired run mode has been selected, press and hold the switch to exit setup and return to run mode.
When the LED chaser is next powered up it will load and start running using the saved mode and sequence. Description of Sequence Data.
To make the creation of the data file easier a set of macros have been defined which are used to create the sequence data. You might want to edit this file as a starting point to create some sequences of your own.
The PIC microcontroller requires programming with the firmware mqnual you can download below. The latest code version 1. The Source code will allow you to create your amnual sequences and then reassemble the code to use them. It’s reasonably cheap to buy and reliable. I have a couple of them and I wouldn’t use anything else now.
Not got a programmer? Buy a pre-programmed PIC from the On-line store. As far as the circuit and firmware on this page are concerned the two are functionally identical and you can use either part. You will however need to make changes to the hardware design and PCB layout to include an external 4Mhz crystal and load capacitors or a ceramic resonator, since the 16F84A doesn’t have the internal oscillator of the 16FA.
MPLAB will generate errors if the code is too big for the device. Can you or how can I make it it run more than 8 LEDs? This is probably the most frequent of the frequently asked questions: There is no quick and easy change to make it a 9, 12 or some other number of LED chaser. If you need a chaser with more LEDs then this project is not suitable for your needs. How can I add more LEDs to each channel?
Yes, since the sequences are user definable you can create sequences that use less than 8 LEDs. I only want it to run one sequence, can it do that? Since the current mode and selected sequence are saved to NVRAM, it always powers up in the last mode and running the last sequence.
Therefore if you select manual mode and the sequence required, it will run only that sequence until you change it. Do the LEDs have to be the same colour? If you want you can mix different coloured LEDs. Can I get the sequences used on the round LED chaser? They are all included in the HEX file available to download from this page. Can you add a button or potentiometer to change the speed?
The sequences don’t have a speed as such, the data for each step in a sequences includes a hold time which has to elapse before moving to the next step in the sequence. This hold time is user defined and can be different for each step in a sequence. The speed a sequence runs at is therefore fixed in the data and there is no option to speed up or slow down a sequence when it is running.
See Description of Sequence Data. Can it run from a 12volt car battery? Yes, should work fine from a car battery. We suggest you include an in-line fuse of mA in series with the power lead to the board. Can you modify the code to run on a PIC type xyz? The code has been written to run on three of the most popular PICs available.
If you want to modify the source code it could be made to run on other PIC types, however we won’t modify the code. See more photo’s of these alternate designs along with PCB artwork.
If you’re assembling from the kit C1 and C3 are the same value, but can be one of two types and will be marked ” C2 is marked ‘. It should be fitted so the notch is in the same mxnual as the marking on the PCB overlay Fig 6. The data used to create the sequences is held in a separate include file.