00:10Hello guys! Welcome to the turn on video of this ESP32 C3 based development board which is the ESP32 2424S012C.
00:19Here the 2424 indicates that this has a display whose resolution is of 240 by 240 pixels.
00:25The S indicates the manufacturer that is Sundan Electronics from China.
00:30The 012 indicates that this falls in the class of standard 1.2 inch displays and C indicates that this
00:38has a capacitive touch inside.
00:40Now let's get into the video.
00:42First of all let's examine the device from its outside.
00:44On the top we have the display itself which is a 1.28 inch round IPS capacitive touchscreen display.
00:51The entire body is built out of plastic.
00:54On the side we can see a type C connector which is for charging the device as well as programming.
00:59Then we have a JST-SH 1mm pitch 4 pin connector on the side which is for UART programming.
01:05Then on the back we have another JST 2 pin 1.25 mm pitch connector for connecting a 3.7
01:14volt lithium battery.
01:15Then we have slots for this boot button, reset button and an on off button on the side.
01:21That's it from the outside now let's open this up and see what's in there.
01:25When we open this up initially we can see that we have internal FPC antenna that's stuck to the body.
01:32Let's try to remove this antenna first.
01:35Now we have revealed the top portion of the PCB.
01:39We have the main part which is the ESP32-C3 board itself.
01:44Then we have this boot button.
01:46We have the reset button.
01:48We can see the charging connector.
01:50We have this UART connector.
01:52You can see the TXRX VCC ground marked in there.
01:55We'll be exploring this whole circuit using this schematic diagram of the device itself.
02:00Now let's start with this type C.
02:02We have the type C connector over here.
02:04You can see that the main pins which are the data plus and data minus.
02:08They are connected to the GPIO pins 19 and 18 which are the D plus and D minus of ESP32.
02:16Now we have a short key diode at the Vout part of the type C which is for reverse current
02:21protection.
02:22Now let's explore the power circuit of this device itself.
02:24We have this battery connector over here.
02:27See, it's connected to the battery charger boost converter IC which is IP5306.
02:34The battery is connected to this pin BAT or pin number 6 of this IC.
02:39Let's see the individual pins of this IC.
02:41We have this VIN which connects to this 5V coming from this type C.
02:47It has an RC filter at the input side for filtering out any noises.
02:51The LED status pins, they are not being used because we have a whole display for displaying the battery status.
02:59Now we have a key pin which is pin number 5 which is connected to this ON-OFF button.
03:05See, on the side.
03:06Now according to the datasheet, short pressing this button enables the output that comes from pin number 8 which is
03:13VOUT BAT.
03:14And double pressing this button disables the output.
03:17It's like turning ON and OFF this device using this ON and OFF button.
03:22Now we have this BAT pin or pin number 6 which is connected to this battery.
03:27Then we have SW pin which is a high frequency switching pin which helps in boosting the 3.7V of
03:33this battery to this 5V output.
03:36Now let's take a look at the LDO used in this circuit.
03:39We have this 3V3 LDO which is A6165P.
03:44Now the duty of it is to take in the voltage that comes from this boost converter and battery charger
03:50IC and give a steady 3V3 output.
03:54Now this 3V3 output is used to power the ESP32 as well as the touch and display drivers.
03:59Now let's come to this boot button.
04:01You can see that the boot button is connected to this GPIO 9 of the ESP32.
04:08It has a pull up of 10K.
04:10When the boot is pressed, it connects to this ground.
04:13If you take a look at this PCB top layer, you can see an empty pad, empty copper pad provided
04:18over here.
04:19See, a round pad.
04:20Now this purpose of this pad is to act as a secondary boot button.
04:26See, it's labeled as S1 in the schematic.
04:28It is also pulled up using a 10K resistor.
04:32Now it's connected to the GPIO pin 8 of this ESP32.
04:36I-O8 is also a boot pin of ESP32.
04:40Now the purpose of this additional boot button is to serve as a backup boot button in case the standard
04:46boot button fails.
04:48Now we have a reset button over here.
04:50See, this is the reset button.
04:51It is connected to this enabled pin of ESP32.
04:55Now it's also pulled up using a 10K resistor.
04:58When the reset is turned on, it connects to this ground.
05:02Now let's take a look at this UR connector over here.
05:05You can see that it's labeled as RX, TX, 3V3 and ground.
05:08Now let's check that in this schematic.
05:10We have it over here.
05:12See, we have this RX and TX pins that connect to this TX and RX pins of ESP32, which are
05:18pin numbers 31 and 30.
05:20Now let me try to split this PCB from the display touch portion and try to reveal you the display
05:25touch circuitry.
05:27Both of the portions are glued together.
05:30Now once I split these two portions, you can see that we have a flexible PCB that connects the two
05:35portions.
05:36If you take a closer look, we can see that it's a 16 pin flexible PCB that connects the display
05:43touch portion to the PCB.
05:44Now let's try to explore the individual pins one by one.
05:48See pin number one, it is ground.
05:51Then we have an LED minus and LED plus pins.
05:54These pins connects to the backlight LED of the display.
05:57These pins turns on and off the backlight LED of the display.
06:01Now we have a VDD, then a ground.
06:03Now this LED pin, it connects to the ESP32 to the GPIO pin 3 via an N channel MOSFET.
06:11See, the N channel MOSFET drives the LED.
06:14Now the MOSFET used here is A290.
06:17You can see the MOSFET over here, which drives the LED.
06:21So it is A290.
06:23Then we have this VDD, then a ground, a ground.
06:26Then we have this SPI pins for display.
06:29The display uses SPI communication.
06:32So we have this DC, CS, SEL, SDA and reset of SPI.
06:37Then the touch uses I2C.
06:40So we have the I2C reset, I2C, SEL, SDA and interrupt.
06:45If you take a closer look over here, you can see a tiny QFN20 package IC over here.
06:51See, you can take a look over here.
06:54See, it's CST816D, which is the touch driver IC.
06:59Now it's mounted onto this flexible PCB.
07:02See, this method of mounting an IC on a flexible PCB is called COF or chip on flex.
07:09Now we have seen the touch driver IC over here, right?
07:12Which is COF or chip on flex.
07:14Now, where is the display driver IC?
07:16We can't see it.
07:16It's not labeled in the circuit.
07:18Actually, the display driver IC, which is GC9A01.
07:24It cannot be revealed in this kind of circuits as an individual IC because it's COG or chip
07:30on glass means it's bonded directly to the glass substrate of this display.
07:37Now, let me try to split this further and show you if we can see the display driver,
07:43which is bonded onto the glass substrate.
07:46Let me try to split this further.
07:53See, now this is the backlight.
07:57Now we have, see, if you take a look over here, you can see the raw IC.
08:01You can see an IC kind of thing, a black thing.
08:05This is the display driver IC, which is bonded directly onto the glass substrate.
08:11This is the glass portion of the display.
08:13It is bonded directly to the glass without an IC package.
08:16This method is used for, you know, keeping it compact and minimal.
08:22And see, this is the raw IC.
08:24You can see small pins connecting to the ribbon cable.
08:28So this is the display driver IC, which is COG or chip on the glass.
08:34Now let's try to power on and see how this thing works.
08:39You know, all things works.
08:41We already have a program running in this.
08:49See, the backlight is powered on.
08:51Now you can see the display is also on.
08:55If they are bonded together, then only we can see the whole thing.
08:58See, the touch is also working.
09:03And this is a torch.
09:05We have a tutorial on our channel.
09:08See the touch brightness.
09:10See the backlight is, the MOSFET is adjusting the current flowing through it.
09:16Let me put them back together.
09:29So that was the teardown video of the ESP32-C3 based development board.
09:34Hope you enjoyed it.
09:35Let's see the next video.
09:36Bye.
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