The big picture in JeeH is still not right: I don’t like the way device drivers run in an exception-centric “handler” mode, whereas the rest of the application uses “thread” mode. This distinction was needed to provide atomic …

JeeH version 6.1.0 release notes and highlights:

This is a minor release. I’m pushing this release out to prepare for some new ideas - mostly aimed at reducing overhead and complexity, and at improving JeeH’s low-power capabilities.

The current …

JeeH version 6.0.0 release notes and highlights:

This is a major new release of JeeH. A lot of things have changed:

• Now you see them, now you don’t: tasks are gone again. The routing of task messages was too complex. Threads are unchanged. Messages …

One of the problems I want to address in JeeH, is how to best interface with peripherals: built-in as well as connected via a common bus, e.g. I2C or SPI. There are two sides to this: talking to built-in hardware via device registers, and talking through …

The DMA-based UART driver in JeeH is an interesting example of the interaction between hardware, memory use, and blocking behaviour.

Reading data#

In JeeH, the way to read bytes from the UART is to send a message to its device driver, and wait for its …

As mentioned in my previous Threads vs Async I/O musings, threads are no longer the main concurrency mechanism I’m after, tasks are. Threads are still present in JeeH (and they actually work), but I’m not so keen on having to allocate stacks …

JeeH version 5.4.0 release notes and highlights:

This is mostly to consolidate what there is, to prepare for a new v6 series of releases (the reason is described in this post - in short: I want to redo the tasks-vs-threads design and the test automation). …

Looks like it’s that time of year again: I’m ripping apart what I have in JeeH 5.3 and reconstructing it in a different way. Perhaps it’s just madness, but I have two reasons to do this: 1) the task/thread design is too messy and 2) the …

JeeH version 5.3.0 release notes and highlights:

This release brings a number of major changes:

• Tasks have been renamed to Threads … because that’s what they really are.

• And with that out of the way: a new Task type has been added, to …

It was a mistake in JeeH to call something a Task when it really is a Thread, so I’ve decided to rename them everywhere in the code and in the documentation. Threads are separate execution contexts, each with their own stack. And that’s …