The goal of this HAT is to provide WiFi, an RTC and 3.3 to 5V step-up for a fast epaper update driving IT8951 as SPI master

Cinwrite DEXA-C097 HAT for parallel epapers

by Martin Fasani's store

$41.73

No tax for United States [change]
Backup battery for DS3231 RTC. Keeps the clock vrystals ticking even if the board is unplugged from USB
Stock available: 2
ESP32
Displays
SPI

New batch of PCBs revision 1.2 has arrived

Trying to make a better price I've invested into buying more quantity hence the price is down 5 USD. Revision 1.2 is exactly the same as v. 1.1 except that has a Seeed Grove I2C connector and ESP32S3 with PCB Antenna.

3D model download Feel free to use this to import in your 3D design program, low polygon some parts removed so it's not heavy, important is to be aware of the size including USB connectors and mounting holes.

Dalian Good Display has now stock of their DEXA-C097 PCB. Please contact Freddie in twitter or in their sales page directly to get their IT8951 boards. Please note also that this PCB, should work with any other SPI display and also with Waveshare IT8951 devices. If you check closely, the Raspberry PI HATs, have also SPI pins available (CLK, MISO, MOSI, etc) We don't need a power hungry PI if we can do it with this PCB. But if for any case you need this combination along 5V you can also drive a Raspberry PI using our product and a Lipo battery.

IMPORTANT: The battery connection polarity should be respected. The power manager TPS2113 does not accept inverse polarity, so if you connect it wrong, it will die with a cause.

What is it?

The PCB is a HAT to use on top of DEXA-C097 (DEXA uses IT8951 just as M5-epaper does but for a bigger resolution of 1200825). Please note that this PCB is pin compatible with an *IT8951 epaper controller** that is actually sold by Good-Display. This is not cheap technology to play with so I recommend getting this ESP32-S3 HAT with 2 MB PSRAM + DEXA-C097 board only if you want to build a product or a industry quality information panel using an epaper display. I recommend developers this ESP32S3 plus the DEXA board for applications that need fast refresh like the e-book readers have. As a demo Firmware and proof-of-concept for this PCB, we built the repository: epaper-weather-station Using that Firmware you can print RTC clock, day, month and temperature just using the data coming from DS3231 on the board. Additionally there are some goodies like sleep at night and wake up with RTC alarm, and added components also for SCD40/41 sensor (CO2 level, precise temperature and humidity)

The PCB is also OSHWA Certified with UID ES000029 so you can check there to access all it's design files and schematics. If you don't want to buy it and want to fabricate it yourself it's allowed, so you can go ahead and use it also commercially. We highly recommend to buy one first to try what is capable of before making some of them!

Why did you make it?

I wanted to use ESP32S3 in a new PCB that also provides a battery charging circuit and a DS3231 real-time clock so you can build a professional product using a 9.7" parallel epaper display with 16 grayscales and 1200x825 resolution. S3 will also provide fast WiFi connectivity and powerful BLE to make a low consumption application. I also made this board to provide a 3.x V to 5 Volt boost converter to the DEXA board below since it needs this voltage.

What makes it special?

At the moment if you want to drive this displays using ESP32 the only chance to do so is to use EPDiy that is a very nice PCB that drives this epapers too. But the waveform is open source and also is slower, meaning that you cannot refresh as fast as using this HAT. So the challenge was to build a PCB that provides:

  • WiFi
  • BLE. Important point: BLE, not Bluetooth classic (Only ESP32 has BT-classic)
  • DS3231 real time clock
  • Fast 40Mhz SPI
  • 3.xV to 5V step-up (And a way to enable this boost converter)
  • 3.7v LiPo battery charger
  • I2C connector (Sensors)
  • Additional SPI connector (With own Busy & CS pin)

SPI pins configuration:

CONFIGEINKSPI_MOSI=11

CONFIGEINKSPI_MISO=12

CONFIGEINKSPI_CLK=13

CONFIGEINKSPI_CS=10

CONFIGEINKBUSY=3


I2C_SDA=7

I2C_SCL=15

I2C has already 4.7K pull-up resistors in place. Enable 5V boost-converter using IO 38 (on HIGH enabled)

#define GPIOENABLE5V GPIONUM38

KNOWN ISSUES

Please check one page presentation PDF. Do not connect SDA & SCL (I2C) pins to DEXA-C097 board below. There is an issue and doing that will block I2C communication. I2C is anyways very slow and not recommended to send the framebuffer to IT8951. Please use SPI to talk to to DEXA-C097 board.

Revision v 1.1

Revision 1.1 comes with an amazing ESP32-S3-WROOM-1-N8 MCU with 2 MB of PSRAM. The PCB comes with a 12 mm coin battery holder and with the battery itself so it can maintain the RTC clock running for at least 5 years. This revision also has a load switch, that is activated on GPIO 38 High, and turns on the 5V to feed the I8951 board below. So this time you can use the epaper controller only when you want and then completely turn it off. It will be optimized for lower consumption and address many of the problems described before.

Check the Hardware repository to see the correct labeling for the board below (This one has already the correct SPI labeling on top)

Links to code and documentation

Documentation (github.com)

Code (github.com)

Design Files (github.com)

Schematics (github.com)

Certified Open Source Hardware - OSHW ES000029

Shipping policy

All electronic products are tested before being shipped. That means you can see connection marks or testing points without damaging the PCB. We pack them carefully with enough care to avoid any cracks and send them always with tracking and insured, so in case they loose the package we both recover the money to get the products again. Please note that spanish post only pays insurance if it's lost, not if it's broken, hence the carefully packed items is the most important step before shipping.

The seller

Martin Fasani's store

Barcelona, Catalunya, Spain
0 orders since Jan 12, 2023
Fasani Corporation designs PCB that help developers have in one single board most of the required features. We use primarily Espressif MCUs and we also like using epaper low consumption bi-stable displays, that keep the image displayed after updating without consuming energy. From time to time we also make HAT adapters for tinypico that is our favourite small ESP32 from Unexpected maker