$20 LCR ESR Transistor checker project

[vinceroger]

we have tried that firmware, we just get a blank screen do you have any ideas what we can try next?

[madires]

Have you double-checked all components (values, pinout)? Even if the display doesn't show anything the tester should stay powered on for some seconds.

[vinceroger]

Hi yes tester does stay on ok  just with a blank screen  i have brought a identical pre built tester so have swopped the atmega328p over to my kit tester and it works fine so has to be the ic, i have tried reading the working atmega328p ic with my promini tl866 and all what happens when you read the chip is a screen of ff s so maybe the chips are data protected some how? i want to get the kit tester working as a spare and upgrade it etc and if we can find the firmware that works it will help others out too who have brought these kits.

[Per Hansson]

Here is a picture of my meter assembled, I have bought the same one as vinceroger.
It was impossible for me yesterday night to see the color bands so I measured the resistors and put them in according to stj's nice reverse engineered component schematic.
That said it's of course possible some of the resistors are 0.1% while some could be 1%, so no warranties there

I now tested another firmware: mega328_st7565 but the screen was blank with that as well.
Do note that our LCD has 9 pins, I note that most other testers use LCD's with a parallel connection and much more pins?

The meter stays on for ca 4 seconds with these firmwares, but stj posted another few on the thread at badcaps.net and with that I got some scrolling text on the screen. (Picture attached).
The behavior with all tested firmwares seems the same though: one press and red LED comes on, backlight comes on then meter turns off after 4 seconds.
With a 5 second long press meter stays on forever and I need to pull the battery to get it to turn off.
I theorize the problem is the same with all firmwares, it's just that the problem is visible with some firmwares :/
As vinceroger mentioned though he bought both the "DIY" meter like me and one preassembled and both his meters work fine with the pre-programmed chip from the seller!

[madires]

Since the tester stays on it's clearly a display problem. The first thing is to identify the display controller and then the pinout.

[stj]

it's using PD0-3

that's about it so far.

[vinceroger]

Since the tester stays on it's clearly a display problem. The first thing is to identify the display controller and then the pinout.

Hi a update so with the help of stj on badcaps.net we have some more information that may help you i have uploaded a picture ot the lcd used on this tester and some information regarding connectors etc ive also checked on the main pcb which pin from the screen connector goes to which pin on the atmega328p ic i hope this information helps
this is from the ribbon cable of the lcd to pcb connector
1 - lcd /CE (gnd)
2 - lcd RST
3 - lcd A0
4 - lcd SCL
5 - lcd SDA
6 - +5v
7 - gnd
8 - led anode
9 - led cathode
this is from main pcb screen connector to the atmega ic
pin 9 goes to pins 22 and 8 gnds
pin 8 goes nc?
pin 7 goes to pins 22 and 8 gnds
pin 6 goes to pin 7 vcc and pin 20 avcc
pin 5 goes to pin 5 pd3
pin 4 goes to pin 4 pd2
pin 3 goes to pin 3 pd1
pin 2 goes to pin 2 pdo
pin 1 goes to pins 8 and 22 gnd
now stj has gave us various firmwares to try but none seem to work can you help guys please remember these ics that came with these kits read as no data on them so will need both files

[madires]

Based on the picture of the LCD module it should be a ST7920, In Karl-Heinz' documentation the ST7920 is stated as "serial" with only three I/O pins (REST = PD0 / B0 = PD2 / EN = PD5). The ST7920 got Reset, CS, SID and CLK, but they got different functions in parallel interface mode. I think the best idea is to check the source code for the functions of the three I/O pins and then to adapt the port pins to match the hardware. You might need to add some code to drive the CS.

[vinceroger]

Based on the picture of the LCD module it should be a ST7920, In Karl-Heinz' documentation the ST7920 is stated as "serial" with only three I/O pins (REST = PD0 / B0 = PD2 / EN = PD5). The ST7920 got Reset, CS, SID and CLK, but they got different functions in parallel interface mode. I think the best idea is to check the source code for the functions of the three I/O pins and then to adapt the port pins to match the hardware. You might need to add some code to drive the CS.

I have never done coding myself so i will ask stj if he or per hansson can help, or if anyone on this site can help modify the coding etc it will be appreciated then we can test these meters.

[vinceroger]

per hansson has been testing some firmware hes found two that sort of work can anyone modify the first one or have the makefile for the second one ? thanks

This firmware works but display is upside down and inverted:
https://www.mikrocontroller.net/topic/248078?goto=4270706#4270706

This firmware works, display is also oriented correctly. But no MakeFile is included.
https://www.mikrocontroller.net/topic/345717?goto=4278544#4278544

[bianchifan]

Based on the picture of the LCD module it should be a ST7920

I do not think so.
Although the pic is of bad quality I'm quite shure it's a display like the fish8840's, ST7565.

When I tried my first flash with K.-H.'s Software my fish showed the same result as described above.
The problem is the contrast, with the default values I coudn't see anything.

Please refer to the manual how to change the contrast on startup or change the default in the makefile.

[stj]

tests will continue when they are awake.
i already built a couple of test files.

[vinceroger]

cheers stj i will give the files a try asap.

[madires]

per hansson has been testing some firmware hes found two that sort of work can anyone modify the first one or have the makefile for the second one ? thanks

So we got confirmation on the controller and the pinout. The next step is to tweak the settings for the display.

[vinceroger]

stj is helping us over on badcaps.net here is the link too the thread
http://www.badcaps.net/forum/showthread.php?t=50720&page=21
im not sure if you have some firmware we can try too madires?

[madires]

Based on the picture of the LCD module it should be a ST7920

I do not think so.
Although the pic is of bad quality I'm quite shure it's a display like the fish8840's, ST7565.

Of course I could be wrong. I've read "LCM_12864_V1.30" on the silkscreen and a quick search for "LCM_12864" lists mostly ST7920 based modules. But you never know

When I tried my first flash with K.-H.'s Software my fish showed the same result as described above.
The problem is the contrast, with the default values I coudn't see anything.

A default setting for contrast is tricky. It will work for most displays but not all. Maybe I should add something about that in the README.

[madires]

im not sure if you have some firmware we can try too madires?

The m-firmware supports the ST7565, but not the ST7920 yet.

[vinceroger]

Ive never done any coding etc so sorry if any of these questions sound daft in any way as per has found two files that do make the tester work up to a point can these be modifed to work?

This firmware works but display is upside down and inverted:
https://www.mikrocontroller.net/topic/248078?goto=4270706#4270706

This firmware works, display is also oriented correctly. But no MakeFile is included.
https://www.mikrocontroller.net/topic/345717?goto=4278544#4278544

[madires]

Based on the controller there are several settings in the Makefile for the k-firmware, such like flipping x or y. If you got the Makefile, change what's wrong and recompile the firmware. Karl-Heinz' documentation explains all the settings and tom666 has posted several guides on programming the ATmega.

[vinceroger]

Thanks for your help guys stj has just uploades some files and ive just programmed the tester although the firware is diffrent compared too my prebuilt kit it seems too work ok so far i will run some tests later regarding my prebuilt unit and this kit  ive built and loaded the firmware on and see if they read the same etc

[eeadata]

I bought this gm328 type color tft lcd transistor lcr / esr kit . I built it but it did not work. When i press encoder switch screen backligt comes on with a white background nothing more.

? am new to atmel stuff. Where to check first ?

[stj]

probably needs programming, a lot of kits seem to be shipped wih blank controllers!!

try to get a refund from the seller or a replacement chip first.
unless everybody does, they will keep getting away with it!

it's not a GM328 btw, those are from EZ-Electronics studio's

[vinceroger]

I bought this gm328 type color tft lcd transistor lcr / esr kit . I built it but it did not work. When i press encoder switch screen backligt comes on with a white background nothing more.

? am new to atmel stuff. Where to check first ?

Have you got a link too the tester you brought too see if its the same one we have been having issues with.

[eeadata]

This One.

[stj]

situation is now,
meter looks working but is reading ESR of 0.00
the fix for the display was NOT using the eeprom for fonts!!! 

here is a post i just made over at badcaps.
----------------------------------------------------------------------------------------------
this whole situation is bullshit - i am starting to think the atmel's are bad.
 here is the makefile for the latest test version

 to break the display output you just need to change

# The USE_EEPROM option specify where you wish to locate fix text and tables.
 # If USE_EEPROM is unset, program memory (flash) is taken for fix text and tables.
 #CFLAGS += -DUSE_EEPROM

that should not happen.
 using the eeprom is standard - that's why it didnt work for so long!!
----------------------------------------------------------------------------------------

so there you have it, maybe the kits arent shipping blank, but the chips are defective.