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Hey PDP-8, meet Raspberry Pi!
If you would like to experience for yourself how a computer such as a PDP-8 looks and feels, there are several possible avenues to choose from:get in touch with a museum, friend, or hobbyist who has...
View ArticleSome amazing software feats
The introduction of the PDP-8 series was a disruptive, game-changing event, in that it made computers available to a large group of scientists, engineers, and tinkerers. For the first time, more or...
View ArticleForget what you know, please
In the beginning, there were computers. Programmed with wires, then with binary data (the “stored-program” computer), then with assembly language, and from there on, a relentless stream of new...
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Dive into Forth
In 1965, computing history was made when DEC introduced a new computer, called the PDP-8 - oh, wait, that was last week’s post.But it applies here too: 1968 was the year when Charles Moore invented...
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DSLs and expressiveness
The KEY design choice in Forth is its dual data- and return-stack. Forth is a stack-oriented programming language. Another characterisation is that Forth is a concatenative language. Here’s what this...
View ArticleI/O, ADCs, OLEDs, and RFM69s
Software development in Forth is about “growing” the tools you need as you go along. Over time, you will end up with a set of “words” that are tailored for a specific task. Some words will end up being...
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Starting Forth on an STM32F1
Here is what we’re after, as Forth Development Environment (would that be an “FDE”?):There are a number of steps needed to use Mecrisp-Stellaris Forth in your own projects (for these articles, we’ll be...
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Dive into Forth, part 2
Switching to Mecrisp Forth implies starting from scratch as far as low-level access is concerned. There’s no C “runtime library” to fall back to, everything will have to be implemented in Forth.This...
View ArticleBuffered serial port interrupts
Mecrisp only implements the minimal serial interface required, i.e. USART1 with polled I/O. This is very limited, because the serial port has no buffering capability: if we don’t poll it often enough...
View ArticleMuch faster SPI with hardware
Unlike an USART-based serial port, SPI communication is not timing-critical, at least not on the SPI master side. Since the data clock is also sent as separate signal, slowdowns only change the...
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Talking to a 320x240 colour LCD
Now that we have a fast SPI driver, we can tackle a more ambituous task of driving a 320x240 colour LCD display. In this example, we’ll use the HyTiny board with this 3.2” display, because the two can...
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The Dime-A-Dozen collection
One attraction of the STM32F103 series microcontrollers, is that there are lots of them available on eBay at ridiculously low prices. There are many variants of this µC, with flash memory sizes from...
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Dive into Forth, part 3
The Forth adventure continues… this is part 3 of a series about Mecrisp Forth on ARM STM32F103 µCs - an amazing environment for interactively trying out the hardware in this well-established chip...
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LCDs need a lot of bandwidth
So far, we have created two display implementations for Mecrisp Forth: a 128x64 OLED display, connected via (overclocked) I2C, and a 320x240 colour LCD, connected via hardware SPI clocked to 9 MHz....
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The amazing world of DMA
There are a lot of features hiding in today’s microcontrollers - even the STM32F103 series includes some very nice peripherals:2 to 3 A-to-D converters, sampling up to a million times per secondon the...
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Reading ADC samples via DMA
Now that we have seen how to push out values to the DAC without CPU intervention… can we do the same for acquiring ADC sample data? The answer is a resounding “yes, of course!”And it’s not even hard,...
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Where is this going?
The last three weeks have been a deep dive into the programming language Forth on STM32 µCs. Results so far have been very encouraging, in terms of using Forth for programming ARM µCs in general.But...
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Diving deep into STM32F103's
Mecrisp Forth 2.2.2 has been flashed onto a new series of boards here at JeeLabs, all with an STM32F103 µC, but of different sizes and with different features on-board.Haoyu Core Board OneWell, it’s...
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The lack of USB support
Those pictures you’ve been seeing in recent articles, with over a dozen boards by now, all have the same configuration in common: boards with a USB port on them, connected and powered through anything...
View ArticleJET and Forth, some thoughts
The JET project is about “creating an infrastructure for home monitoring and automation” (it’s actually considerably more, but this is a big-enough bone to chew on already…).Note that JET is not about...
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