Swordfish Code Examples

This tip is almost trivial, but it's a D'uh moment too.  Just in case anyone else has missed the obvious. here's a quick tip.   I usually use Swordfish's hardware UART routines and I don't recommend Swordfish's software UART for input, where there are some "gotcha's."  The software UART does work great for output. A UART output is often handy for keeping an eye on program parameters and status.  I usually use the hardware UART,...

A square wave generator can be handy for simulating sensors and providing an input to a micro-controller.  This signal generator can be adjusted from 10 Hz - 10 kHz, with an adjustable duty cycle from 1 to 99 percent.  

I recently purchased a couple of the Parallax RFID readers (#28140) that were on sale at Radio Shack. These are similar to the one Graham used to develop his code, so I wanted to see if the code would work. I'm happy to report that the code does work for this RFID reader with no changes, but some bumps along the way provide some useful troubleshooting tips.

To verify that the DS18B20 tutorial does indeed work as written, I wanted to test it out.   Equipment: DS18B20 temperature probe from Sure Electronics (convenient package - a bare part would work just as well) TAP-28 board, equipped with an 18F242 processor and 20 MHz crystal (2) PICkit 2 - for convenience, 1 used for programming, 1 for UART tool   Procedure (with timeline): 1:00 Begin. Gather hardware together on top ...

A simple program that generates some LED patterns. I wrote this to help someone else out on another site, and thought it would be worth sharing here? The patterns are (in order of sequence): Left to right Right to left Center to outside Outside to center All flashing   The Result Results are usually more interesting then how-you-got-there, so here they are: (A simple circuit. 2N2222 NPN transistors could be used to switch banks of...

EM4100 readers are somewhat popular because they are cheap, widely available and easy to use. You can pick up an EM4100 RFID reader for ~$40 or less. The module used in this example may not work for every EM Reader out there - though it offers an approach to start with. If you do create a new module for a different device, then please share it here at digital-diy.com

This program was the result of a recent issue a digital-diy.com member had regarding SD Cards. It also provides a means to benchmark the speeds of different cards and software configurations. Please ensure you are using the latest version of SDFileSystem.bas (at time of writing: 4.1.4). If you are updating (or do not...

The LS20031 GPS Module supports up to 32 Channels and outputs at 5Hz. That's some serious specs and a will serve the needs of almost any GPS application! Also, the LS20031 GPS receiver includes an embedded antenna and GPS receiver circuits. It is a low-cost unit which outputs an astounding amount of position information 5 times a second. The receiver is based on the proven technology found in LOCOSYS 32 channel GPS SMD type receivers that use MediaTek...

PORTBinterrupts are used for instantaneous response for changes to Pins 4, 5, 6, 7 on PORTB. Further more, the interrupt will even wake the PIC from a Sleep instruction, so your device can be in low power mode (the PIC can draw as low as 0.1u Amps while in Sleep mode), and be instantly awoken when there is a change on PORTB. One precaution to be aware of is not to forget to read the contents of PORTB within the ISR (Interrupt Service Routine). This...

Context Saving and Restoring is vital for interrupts, as the program could get pulled from  anywhere at any time. What this means is that the system variables/registers are backed up at the start of the Interrupt Handler, and then when the Interrupt is complete, they are all restored again.   This can be a little memory demanding, so you only want to back up what you need to. Consider this, your Interrupt uses a function that is also used...

Swordfish will also handle the priority of your Interrupt Service Routines (ISR's). 18F PIC's support twp different Interrupt priority routines. These are known as High and Low Interrupts. If you require an interrupt that needs priority over everything else (including other interrupts), then you must let the compiler know by setting its priority, eg, Const
ipLow = 1,
ipHigh = 2
 
Interrupt OnTimer1(ipLow)

Author: Graham

Read More...