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Python Multi-core / GPU Digital Phosphor Rendering of Huge Waveform Data

Most modern oscilloscopes are marketed as Digital Phosphor Oscilloscope (DPO) because the waveform shown on those scopes looks night-and-day compared to their old counterparts.   DPO vs DSO, from Tektronix TDS784D marketing materials This is because although the traditional DSO can capture data at a blazling fast speed, they lacked the processing bandwidth to show them on the display: It may be able to capture 100 million waveform data for one trigger point and store it in the sample memory, but the monitor only has say 1024 pixels wide. DSO simply throw away most of the points, resulting in an ugly aliased apperarance with 1bit per pixel.   To achieve the nice and smooth look of a DPO, what we want to do is to down sample the 100 million points to 1024 pixels wide with a correct down sampling algorithm.  Recently I've been working with some huge waveform captures with more than 1G points. Plotting such data with the beloved matplotlib will result in an ugl...
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A Modern Reincarination of Graphire: WACOM Bamboo Series Drawing Tablet Reverse Engineering

This is going to be a short follow-up of the previous article; please read that one before proceeding:  https://www.lithcore.cn/2024/02/wacom-et-0405-reverse-engineering.html.

Same as before, all the high-resolution PCB scans have been uploaded to GDrive: https://drive.google.com/drive/folders/1vGHHMH9WkavLYoCPT2HWrooUTZOjV1wc

I'm personally attached to the Bamboo product line because that is where I got started 10 years ago. The Bamboo product line is initially made of cheap pen-tablet products designed for the entry-level market. WACOM intentionally limited the performance of those products to avoid direct competition with their professional Intuos product line. 

Interestingly, by the time I started using their products, WACOM had gradually shifted the focus of this product line to experimental and high-diversity products, including mobile phone styluses, ultrasonic pens (The first Bamboo Inkling product), mobile phone applications, and paper-based products (e.g. Bamboo Folio and Bamboo Slate). Meanwhile, the low-end pen tables have been relocated to the "Intuos" (not "Intuos Pro") line and, subsequently, the "One" product line.

CTH-470

This article is about the Bamboo CTH-470 pen tablet. Surprisingly, the design is almost identical to Graphire's, with no ASIC chips on board (except for the one in the pen). It's quite unusual, considering WACOM's tradition of making ASIC chips since the very beginning.

Backside of the PCB

Captured Waveform at the Integrator's Output

The output waveform is simplified compared to Graphire's. Notice that the pressure resolution has been upgraded to 10 bits instead of 8 bits.

This model also supports capacitive touch using an Atmel chipset. 



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