Kensaku Kuboya

Senior Legacy Embedded & Industrial Systems Engineer | C/C++ | FreeRTOS | BLE | Legacy Modernization | Hardware/Software Debugging | Japan

[Kensaku Kuboya @kuboyadev]

No author in sight.
The documentation is ancient history.
Yet, tomorrow, it must run.
For over 25 years, I have been keeping that software alive.
This is the story of who I am. Read it on Medium.
https://t.co/e0qTntiE9y

[Kensaku Kuboya @kuboyadev]

3/ I didn't rewrite everything.

Working low-level mechanisms stayed.

The goal was to make ownership explicit and change the system incrementally on real hardware.

I wrote the full case study here:

https://t.co/Yu9w74dN0b

#EmbeddedSystems #FreeRTOS #Firmware

[Kensaku Kuboya @kuboyadev]

1/ BLE sometimes failed after disconnect.

LED and buzzer effects conflicted.

Flash writes disturbed periodic processing.

Debug worked.

Release failed.

Adding another if or another flag would only make the system harder to understand.

[Kensaku Kuboya @kuboyadev]

2/ The real question became:

Who owns this state?

I separated:

• application state transitions
• hardware effects
• BLE events
• persistent storage
• time-critical processing
Queues and EventGroups replaced some of the informal Boolean signaling.

[Kensaku Kuboya @kuboyadev]

Too many flags. Not enough ownership.

I refactored legacy FreeRTOS firmware where BLE, ADC, Flash, LEDs and timers had gradually become tangled through shared state.

The bugs looked random.

They weren't. 🧵

[Kensaku Kuboya @kuboyadev]

A timeout inside the application is useful.

A timeout around the application is a reliability boundary.

Here is what I learned while recovering hung BlueZ state on a Raspberry Pi BLE collector:

https://t.co/H2wLP5i82o

#EmbeddedSystems #BlueZ

[Kensaku Kuboya @kuboyadev]

@simpleCheena Indeed. Keeping ISRs short and deferring I/O to tasks makes the timing behavior much easier to reason about.

[Kensaku Kuboya @kuboyadev]

I removed Flash/KV Store writes from a 10 ms FreeRTOS timer callback.

The problem wasn’t Flash itself.
The problem was making real-time processing depend on unpredictable storage latency.
Small change. Much cleaner timing boundary.

[Kensaku Kuboya @kuboyadev]

I wrote up the engineering decisions and trade-offs on Medium.
https://t.co/V95S4PFL6K
#EmbeddedSystems #FreeRTOS #Firmware #CPlusPlus #RTOS

[Kensaku Kuboya @kuboyadev]

Full write-up on Medium:
https://t.co/zsGRBsHaVB

#EmbeddedSystems #Firmware #Cpp

[Kensaku Kuboya @kuboyadev]

Debug works. Release fails.
The bug was hidden inside an assert.
CY_ASSERT(initialize_storage() == SUCCESS);
In Release, the assert disappeared.
So did the initialization.
I wrote about how I found it and why this pattern is dangerous in embedded firmware.

[Kensaku Kuboya @kuboyadev]

@BookIntroduces スタバが数分車に乗らないといけないので裏山である。なのにスタバカード作ろうかと思ってる。

[Kensaku Kuboya @kuboyadev]

Amazon Musicにある宇多田ヒカルのGold　～また逢う日まで～を紹介します https://t.co/NTve68woAO

[Kensaku Kuboya @kuboyadev]

ぐぬぬ！

[Kensaku Kuboya @kuboyadev]

王様ランキング人気あったのは知ってたけど横目で眺めてるだけだった。見始めたら一気見してしまった。そしてこの作者にも40過ぎて夢実現させたってことにちょっと感動した。

[うめちゃん/クリエイティブ教育 @umechan_manabi]

🌸コウペンちゃん好きに届け🌸

こんなにも愛溢れる方がDiscordコミュニティ作られてます。

「コウペンちゃんは皆のものだし…」って作る時とても悩むほど真面目な人です。上下なく分け隔たりなく、皆平等に愛せるように。

ファンの方一度覗いてみて！🙏　

#拡散RT希望
👉 https://t.co/zKed0RtWfZ

[Kensaku Kuboya @kuboyadev]

なぬお！？

[Kensaku Kuboya @kuboyadev]

さて、明日から（今日から⁈）実装始めるぞ。

[Kensaku Kuboya @kuboyadev]

今日もflutterの設計で試行錯誤。ネット上の情報がほぼ2020年から2021年辺りが1番活発で最近はもう落ち着いちゃってる感じ。今更ながらflutterと言う感覚がひしひし伝わる。アーキテクチャに関しては、クリーンアーキテクチャ、リポジトリパターン、MVVM、Provider辺りで

[Kensaku Kuboya @kuboyadev]

AndroidのJavaアプリを作った時と同等な感覚で使えそう。Stream とStreamBuilder が、LiveDataとObserverという関係に近い。後はデータベース周りでRoomに近いパッケージはあるけどこれだと言うものがない。SQfliteでとりあえず言っとく。今あえてBLoCを選択する理由はなさそう。