$20 LCR ESR Transistor checker project

[madires]

I already connected the LCD_CS to the PB3 and I had a white screen all the time without even showing the firmware version.

Because PB5 is still connected to /RES the rotary encoder would trigger a reset. LCD_CS can't help with that, but with LCD_SDA (PB7) since it would prevent the LCD controller to take in data when the rotary encoder is read.

[Szybkijanek]

So, LCD ST7735 works good now with this config:

Code: [Select]

#define LCD_PORT         PORTB          /* port data register */
#define LCD_DDR          DDRB           /* port data direction register */
#define LCD_RES          PB4            /* port pin used for /RESX (optional) */
//#define LCD_CS           PB3            /* port pin used for /CSX (optional) */
#define LCD_DC           PB5            /* port pin used for D/CX */
#define LCD_SCL          PB6            /* port pin used for SCL */
#define LCD_SDA          PB7            /* port pin used for SDA */or this

Code: [Select]

#define LCD_PORT         PORTB          /* port data register */
#define LCD_DDR          DDRB           /* port data direction register */
#define LCD_RES          PB4            /* port pin used for /RESX (optional) */
#define LCD_CS           PB3            /* port pin used for /CSX (optional) */
#define LCD_DC           PB5            /* port pin used for D/CX */
#define LCD_SCL          PB6            /* port pin used for SCL */
#define LCD_SDA          PB7            /* port pin used for SDA */Thanks guys!

[de_light]

Very sorry if this has already been asked: is there a way to program the GM328A in circuit? Does anyone have the ICSP pinout? Or do I have to remove the Atmel chip and program it separately?

[madires]

Yes, but you need to solder six wires and somehow glue the header onto the PCB. The procedure is quite simple, e.g. https://www.instructables.com/Adding-ICSP-header-to-your-ArduinoAVR-board/.

[de_light]

Thanks madires. Are the ICSP pins broken out anywhere on the board though?

Edit: It doesn't appear so.


PS: I found this schematic that an EE has reverse-engineered for the GM328A during my searches.


https://dragaosemchama.com/en/2019/04/gm328a-reverse-engineering-new-firmware-and-tetris/

[madires]

MISO, MOSI and SCK are connected to test resistors, and RESET has a pull-up resistor. So you could solder the wires either directly to the ATmega or to the resistors which might be easier. For a schematic with designators please see https://disk.yandex.ru/d/yW8xa5NJgUo5z/GM328A.

[de_light]

...

Please, madires, or @indman if you are reading. I'm really struggling with compiling this. After spending three hours on it this evening, I finally managed to compile and upload to the Atmel328P using USBAsp and my Arduino as a shield.

However, when I load up my GM328A, all I get is a white screen. I read the 1.43m documentation and it makes reference to the LCD_SEMI_ST7735 and I used these values. Would you be able to take a look at my code from config_328.h and see where I'm going wrong? 

Code: [Select]

/*
 *  ST7735
 *  - 4 wire SPI interface using bit-bang SPI
 */

//#if 0
#define LCD_ST7735  /* display controller ST7735 */
#define LCD_GRAPHIC /* graphic display */
#define LCD_COLOR   /* color display */
#define LCD_SPI     /* SPI interface */
/* control and data lines */
#define LCD_PORT PORTD /* port data register */
#define LCD_DDR DDRD   /* port data direction register */
#define LCD_RES PD0    /* port pin used for /RESX (optional) */
#define LCD_CS PD5     /* port pin used for /CSX (optional) */
#define LCD_DC PD1     /* port pin used for D/CX */
#define LCD_SCL PD2    /* port pin used for SCL */
#define LCD_SDA PD3    /* port pin used for SDA */
/* display settings */
#define LCD_DOTS_X 160 /* number of horizontal dots */
#define LCD_DOTS_Y 128 /* number of vertical dots */
//#define LCD_OFFSET_X     4               /* enable x offset of 2 or 4 dots */
//#define LCD_OFFSET_Y     2               /* enable y offset of 1 or 2 dots */
//#define LCD_FLIP_X                      /* enable horizontal flip */
//#define LCD_FLIP_Y /* enable vertical flip */
//#define LCD_ROTATE /* switch X and Y (rotate by 90�) */
//#define LCD_BGR                         /* reverse red and blue color channels */
#define LCD_LATE_ON /* turn on LCD after clearing it */
/* font and symbols: horizontally aligned & flipped */
#define FONT_10X16_HF /* 10x16 font */
//#define FONT_6X8_ISO8859_2_HF           /* 6x8 Central European font */
//#define FONT_8X8_ISO8859_2_HF           /* 8x8 Central European font */
//#define FONT_10X16_ISO8859_2_HF         /* 10x16 Central European font */
//#define FONT_8X16_WIN1251_HF            /* 8x16 cyrillic font */
//#define FONT_8X16ALT_WIN1251_HF         /* 8x16 alternative cyrillic font */
#define SYMBOLS_30X32_HF /* 30x32 symbols */
/* SPI bus */
#define SPI_BITBANG       /* bit-bang SPI */
#define SPI_PORT LCD_PORT /* SPI port data register */
#define SPI_DDR LCD_DDR   /* SPI port data direction register */
#define SPI_SCK LCD_SCL   /* port pin used for SCK */
#define SPI_MOSI LCD_SDA  /* port pin used for MOSI */
//#endif









Also, in config.h I have uncommented #define HW_ENCODER. Further down the file, there is also

Code: [Select]

/*
 *  check for rotary encoders
 *  - uncomment to enable
 */

#define SW_ENCODER
Am I correct in having this uncommented?

[indman]

de_light,the Clones file contains a working configuration for the AY-AT clone (GM328A),which you can take for a sample configuration config_328.h
You have a clone with a standard RGB display.

[de_light]

Is the clones file found in the github transistor tester warehouse? (madires)

[madires]

The "Clones" file is included in the firmware's tar.gz archive, i.e. you have it already in the directory with the source code.

[Andbro]

Hi,

Do you can tell me what is this model LCD ? It's on new Chinese GM328A clone.

thank

[madires]

Does the display module have an additional IC (U3) after the level shifter? If so, then it's some unknown LCD controller and U3 is an MCU emulating an ST7735. It will run with the semi-ST7735 driver.

[Yuriy_K]

Firmware for GM328A with display of different Gamma. Last modified Ttester Karl-Heinz Kübbeler 1.13k + color
Changed some colors in the BGR version

[Andbro]

To the latest question from Madires, yes an unknown MCU is used to emulated the display.

Thank for the firmwares from Yuriy_K. Does this firmware is for programming only the AT328 or it's for programming the unknown MCU ?
How to check if my display is RGB ou BGR ?

The display is very dark compared to the original display. Someone knows how to increase the intensity of the back light ?

Many thank

[madires]

Yuriy_K's compiled firmwares are for the ATmega. If you use a firmware with RGB color scheme but blue and red are reversed during output you have a display with BGR color scheme. Most display controllers allow you to change the color scheme via command. However, the MCU emulating an ST7735 doesn't support that. Therefore the firmware needs to reverse red and blue also. Regarding the backlight you could try to change the dropping resistor for the LEDs carefully.

[Yuriy_K]

Regarding the backlight you could try to change the dropping resistor for the LEDs carefully.

220 resistors installed, can be downgraded to 120-150 

[indman]

@Andbro and to all!
Those with a dim screen on the AY-AT(GM328A-B)!
In the power supply circuit of the screen backlite there are as many as two current-backlight resistors in series 220 ohms and the amount 440 ohms.
One stands on the red(black) board(red arrow in photo). I replaced it with a short jumper.
The second one is on a board with a display.
For normal visibility of the screen it was necessary to change it to 100 ohm resistor.
The consumption of current on the battery became 47mA screen is perfectly visible.

[Andbro]

My model is like on the pictures. The resistor for the display was a 510R (440R on PCB). She was replaced by a 220R. I will see if i must replaced by a 100R.

thank

[indman]

Andbro,you have a new type of circuit board that has not yet been considered in the forum.

[de_light]

Thanks both. Working now!

[ko4nrbs]

I have a rarely used M644 Tester that will not power on.  Can't see well enough o figure it out and even if I did I'm not set up for surface mount soldering.  Anyone out there that would check it out for me?

Bill

[indman]

Hardware upgrade and update mod m-firmware 1.43m,k-firmware 1.13k for clone LCR-TC1!

Hardware:
1. Removed the ATmega324PA chip. In its place, the Atmega644PA chip is installed.
2. Removed the STC15L104W chip. In its place,a small circuit board with a power management scheme proposed by madires is installed.
3. A 5-pin joystick is integrated into the circuit for more convenient control of the tester.
4. Additional parts are installed for the successful operation of the frequency meter and generator modes. To do this, I used miniature MMCX connectors.All additions are presented on the schematic diagram in the archive.
5. Instead of resistor R5(8k2), a resistor with a nominal value of 9k1 is installed. This reduced the input voltage of the 78L05 from 9.4V to 8.5V.
The test voltage of the zener diodes has decreased from 43V to 40V.
All the necessary materials for repeating my improvements are presented in the attached archive.

[indman]

Only for chip ATMega644 16Mhz!
Firmware:
The changes in the firmware are made to my personal taste and for a more visual and convenient control of the device's operating modes.
Improved the 8x15 font, added large question and zener symbols, as well as the standard inductance symbol.
Added a color battery status indicator. The "OK" and "WEAK" statuses are no longer displayed, but the "LOW" status remains.
The GUI and the color palette in 1.43m Mod and 1.13k Mod are made in the same style. These are my preferences.
Thank you to dear madires and Yuriy_K for your valuable advice and help!
In the archive, I compiled the firmware english for 3 variants of the clone's circuitry:
1. With the rotary encoder installed.
2. With a 5-pin joystick installed(this is my option)
3. Only one standard Test button.
I do not publish or distribute the modified versions source files. If madires likes my suggestions,I will send him all the necessary materials and he can easily use them in the next relised.

[Obelix2007]

I have a rarely used M644 Tester that will not power on.  Can't see well enough o figure it out and even if I did I'm not set up for surface mount soldering.  Anyone out there that would check it out for me?

Bill

... for this topic I had a contribution in the forum:

https://www.mikrocontroller.net/topic/transistortester-avr?reply_to=6439712#6439712

contribution-TIME 14.10.2020 06:18

This are the GOOGLE-TRANSLATE:

Wilhelm K. wrote:
> How did you unsolder it?

Hello Wilhelm,

first I separate the solder pins directly on the TQFP housing with a
Carpet knife off. Now I can remove the pin scraps from every single PAD
unsolder. Then comes the removal of the excess solder
from the pads using end braid. Then clean with appropriate
Solvent, fix the Mega644 first with a corner pin and
align carefully, then solder on the opposite pin,
now there are only 42 left.

Then I removed the 8-pin U4 using the same method and
there the one made beforehand on a small piece of breadboard
2Transistor solution of the TC-1-MOD from Markus connected.

Before working on the controller, however, I first have the start button
away. Its solder points on the board are the right distance
for the rotary pushbuttons already known from other clones. The
Rotary encoder still needs a small 1mm hole for its GND connection
for which there is already a marking in the right place on the circuit board
is available. Next there must be a conductor path from the button connection to the
Encoder connection are severed and the other
Encoder connector on the front and back of its circuit board
respective 4 thin ground connections are released.

A 1kOhm resistor each leads from the encoder connections to the VCC
Connection and a 10kOhm to the control pins of the controller (PB5; Pin1 and
PB6; Pin2).

In addition, I have an opening for three in the side of the case
further connections are provided that connect the output (PD4; Pin13) of the
Frequency generator or PWM generator, the input for the
Frequency measurement (PB0; Pin40) and a GND connection are available
represents.

Greetings Horst

P.S. I have not (yet) exchanged the voltage regulators.

[madires]

I have a rarely used M644 Tester that will not power on.  Can't see well enough o figure it out and even if I did I'm not set up for surface mount soldering.  Anyone out there that would check it out for me?

Let's do some simple checks first. Does the LCD's backlight turn on when you press the start/test button (it should stay on as long as you press the button)? For a schematic please see https://disk.yandex.ru/d/yW8xa5NJgUo5z/Hiland%20M644.