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Tearing effect - ST7789
09/25/2023 at 10:01 • 0 commentsTypically, screen tearing occurs when the buffer is insufficient for the screen size or the refresh rate is slow. However, in my case, the display was set to refresh at 60hz, however in my case, the esp32 was not fast enough to achieve 60hz when used with lvgl. The optimal solution in this case is to change the scanning frequency of st7789, in my case the value 0x1a is suitable.
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Integrated logic analyzer - Sigrok Pulseview
09/17/2023 at 09:36 • 0 commentsHello, I'm back.
A Logic Analyzer is an indispensable tool for debugging electronic circuits, and Felini will have this feature. Most of the logic analyzers currently not made by Saleae use fx2lafw, running on the FX2 chip series with the GPIF peripheral. This peripheral allows direct data transmission from GPIO to USB, without involving the CPU. As a result, the FX2 with an 8051 core still delivers remarkable results. Due to the USB bandwidth limitations, logic analyzers running the fx2lafw firmware are capped at 24MHz. Unlike the FX2, the ESP32 lacks GPIF; however, in theory, the ESP32S3 can capture at up to 80MHz (maximum), which is the goal I am striving to achieve. Felini LA will work with the open-source software Sigrok PulseView, using the SUMP protocol to transmit data over USB CDC in the background. To be honest, I wish to implement a different protocol on the ESP32S3, allowing it to maximize the hardware USB speed and have liveview capture capabilities. However, time constraints do not permit me to do so.
Additionally, the number of samples and channels also need to be considered. Based on my own experience, I will prioritize the number of samples over the sampling frequency. Below is an update on progress and achievements: Pulse has recognized Felini and is operating at a relatively low speed.
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ESC/Servo Test
08/21/2023 at 08:03 • 0 comments
The tool that Felini will replace in this log update is an RC ESC/Servo tester. Servos require a pulse frequency of 50Hz, with active-high time ranging from 0.5ms to 2.5ms.If you don't want or don't have a blue-colored Servo tester like the one in the picture, you will need to invest some time in coding and generating PWM pulses... just to set the rotation angle or check if the servo is actually functioning. This is unnecessary when you have Felini.
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Similar to a voltmeter but more visual
08/19/2023 at 15:50 • 0 commentsI am still dedicating time to focus on the development of Felini, and the source code will be open in a few weeks, once everything is running smoothly. Felini utilizes INA226 to monitor the output voltage after communicating with the Type C PD power supply. When not using the power delivery feature, INA226 is utilized to transform Felini into a wide-range voltmeter with voltage coverage from 0-24V, sufficient to meet most needs in a DC lab environment. A notable difference from a regular voltmeter, Felini is equipped with a display, so we will have a small graph that makes it easy to observe voltage fluctuations that need to be measured.
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Testing CMSIS - DAPLink
08/07/2023 at 09:14 • 0 commentsWhen I started concept prototype of Felini, I wanted to quickly determine if the Felini project idea was actually viable, and one of the parts I thought was the hardest part was implementing a DAPLink suite on esp32s3 , which no one has ever done before.
And I got lucky, DAPLink runs stable on esp32s3 with cherryusb stack. At the time I started testing DAPLink porting on esp32s3 (March-2023), cherryusb stack only supported esp32s2, and I had to overcome another challenge, which was implementing cherryusb on esp32s3.
As you can see, DAPLink works on Felini, with an intuitive pin connection interface on the screen, no need for diagrams, extremely simple to use.DAPLink shows up on windows as CheryCMSIS-DAP and comes with a usb to serial portDAPLink shows up on windows as CheryCMSIS-DAP and comes with a usb to serial port.
And as expected it works with openocd.
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2nd prototype
08/04/2023 at 16:50 • 0 commentsThe next version took some time to complete. From the initial concept, this is the third hardware version I designed. It has added an extra battery to enable standalone operation without the need to plug in a USB cable.
To power on or off the device, I utilized the AXP173 power management IC. This IC allows you to press and hold the power button to turn the device on or off. It manages power, charges the battery, and automatically switches between USB and battery power in a compact size (5x5mm), replacing multiple ICs for these tasks and saving PCB space.
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First Prototype
08/02/2023 at 16:02 • 0 commentsThe first version of FELINI was a device consisting of 2 larger and rougher circuit boards compared to the current version, and it was not designed with an integrated battery. This means that it could not function without being connected to a laptop, external power source, or powered through the connectors located on the bottom side.
This version was overloaded with numerous complex features and nearly non-functional due to missing components, as some of the parts couldn't be ordered. As a result, it only made it to the stage of 3D-printed casing assembly testing.
The next version was attempted with modified component footprints, but it still didn't work, mostly due to my mistakes and errors during the design process. Therefore, I decided to start a completely new version of FELINI, which is the current version we have now.