Making noise with a SN76489 Digital Sound Generator – Part 3

In the first part and second part we examined the basics of the SN76489 hardware and the development of a library to manage sound production from this IC.

So, after all this effort, what kind of sound does this hardware produce? In this final post I run a few tests and dig into the resulting waveforms.

Continue reading “Making noise with a SN76489 Digital Sound Generator – Part 3”

Making noise with a SN76489 Digital Sound Generator – Part 2

In the first part we examined the basics of the SN76489 hardware and how to manage it at the hardware interface between MCU and IC.

To enable sound generation experiments, the first thing I did was create a library to allow me to write sketches without worrying too much about this underlying hardware management.

Continue reading “Making noise with a SN76489 Digital Sound Generator – Part 2”

Making noise with a SN76489 Digital Sound Generator – Part 1

Most computer games from the 80’s are recognizable by the bleeps and bloops they produced for sound. The easiest way to do this to toggle a single I/O pin to generate a square wave but there are some retro sound ICs that allow us to do much better for a minimal investment.

The SN76489 is one such IC that is still available at a very modest price and is easily interfaced to modern microprocessors.

Continue reading “Making noise with a SN76489 Digital Sound Generator – Part 1”

Combining Arduino Sketches

Beginners love Arduino coding because there is so much of it available to just copy, load and go without too much thinking required.

Then they find that one thing they want to do is in one sketch and another in a second sketch. All they need to do is combine these sketches! This can be a big hurdle the first time it happens and many fail to get a satisfactorily working product.

There is a systematic approach to this that helps to ensure that things work.

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Finite State Machine Programming Basics – Part 2

The first part of this article introduced a simple Finite State Machine through the exercise of transforming the standard linearly programmed Blink example into a FSM style application.

In this part we’ll look at other common embedded applications and how they can be coded using FSM techniques.

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Finite State Machine Programming Basics – Part 1

Many beginner programmers, once they go beyond the ‘blinking LED’ code, get blocked by not being able to do more than one thing at once. In many cases they are directed to the ‘Blink WithOut Delay’ code (BWOD) as a hint about what to do, but this soon also runs out of steam. BWOD implies, but does not make explicit, a Finite State Machines (FSM) approach.

In this article we’ll evolve the simple linear Blinking LED sketch into a FSM to illustrate the difference in approach.

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Persisting Application Parameters in EEPROM

When an application starts, any data was was part of a previous execution is reset to the initialised values of the variables. Often, however, it is desirable to maintain configuration and state values between processor resets. EEPROM is a good option to store these values.

This article explores ways to make this task easy.

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Are Strings really that Evil?

One of the many repeating themes on the Arduino forums is the use of Strings (with a capital ‘S’) against usings strings (with a little ‘s’) – the former refers to a class that encapsulates string handling and the latter refers to the use of nul terminated char arrays.

The kind of forum threads involved are generally someone who wants to use Strings and is having a problem followed by a lot of other posts telling them not to because they are ‘bad’.

So what makes them ‘bad’ and is this really a problem?

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Parola A to Z – Optimizing Flash Memory

RAM_Chip

A question that often arises is how to ‘save program memory’ when the MD_Parola and MD_MAX72xx libraries are used in an application. In this article we’ll cover how you can do this using the facilities already built into the library code.

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TCS230 Revisited – Frequently Asked Questions

TCS230 Sensor

My first post about calibrating TCS230 RGB color sensor has consistently been the most read article on the site. A lot of readers have also used the MD_TCS230 library to write their own sketches. A few questions, however, have consistently been asked on forums and via email about the sensor and the library. Here is a collection of these FAQs and their answers.

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