ESR meter upgrades

[stj]

Re: ESR meter upgrades

well the hitachi displays are character displays - so even the biggest (40 x 4) only needs a 160byte packet for a complete refresh.

the spi displays are bitmapped 160 x 128 or bigger.
so 3bytes per pixel = 6K per refresh.
to make it worse, most testers dont use the hardware spi or i²c pins - they bitbang the data.

as for porting to an ARM cpu, the problem is the cpu needs to be running at 5v.
unless you want to add seperate ADC / DAC chips.

[eccerr0r]

Re: ESR meter upgrades

Well, thought the HD44780 was quite fast or at least "more than fast enough" when the code/interface is written right... and if lazy it's a slug. Hoping that this SPI color LCD interface, even if it's only 16-bit, is not affected the same way.

[redwire]

Re: ESR meter upgrades

HD44780 runs really slow, I think its internal clock is a few hundred kHz. The 1,000nsec (data) cycle time gives it away. I used the Busy Flag once and it was so slow and F/W could hang if the display did not respond, they do crash due to ESD.

I 'd like to see the ESR Meter ported over to something ARM-core like SAMD21G18. 256KB FLASH, 32KB RAM, 48MHz.

[stj]

Re: ESR meter upgrades

the pp3 lasts forever - it can run one down to about 6v and still function fine.

HD4470 is an interesting case,
it has a "busy" pin/flag.
if you watch it between transfers it runs fast, but a lot of designs save a pin by just using fixed delays between writes.
also it can run in 4bit or 8bit mode

[eccerr0r]

Re: ESR meter upgrades

TBH I've seen HD44780 updates really slow too, and that's parallel even - except written/designed poorly. I just wonder if the same is with AVRtester or not, lazy programmers or not...

My PSU project I was working on with the HD44780 display, designed/written "properly" I was able to get it to update autorepeat keypad buttons on the screen without it skipping, and still change the numbers faster than the numbers can be read. Then I see other implementations that can only update once per second... Boo!!!

Now I wonder how long these things last with a PP3 battery or is it not worth it, and have to use a Li-ion pack...

[stj]

Re: ESR meter upgrades

color display slows the UI because it takes 3 times the data to be sent over the spi bus for each refresh.
if you change the crystal to 20MHz and re-flash the firmware it runs much better.

[eccerr0r]

Re: ESR meter upgrades

Finally got my avrtransistortester... took enough time, so much for china shipments.

It came with a crap solderjob, had to reflow it before the display (rgb color) would work.

Pretty interesting. device. Crappy slow UI... wonder if other versions are as slow...

Now...3d printed case for the device, hah...

[stj]

Re: ESR meter upgrades

most people use stripboard on wires

[clearchris]

Re: ESR meter upgrades

Damn, that's a lot to fit on a small pad. Are people soldering in small boards? At a point, I think it would be better to splice in an on/off switch on the line to the battery.

[stj]

Re: ESR meter upgrades

the bin files arent a real fix.
this is:

[clearchris]

Re: ESR meter upgrades

you can reprogram the stc micro on a tc1 - it still crashes out of sleep mode though.

Hmm, I saw a reference to using the two transistors or reprogramming the u4. Maybe it was with the assumption that the reader does the programming. I have however seen .bin files for the u4 mcu though in that thread, I wonder what they do...

[stj]

Re: ESR meter upgrades

you can reprogram the stc micro on a tc1 - it still crashes out of sleep mode though.

[clearchris]

Re: ESR meter upgrades

if it's a large button and not a 5mm one then a rotary fits the pads.
i'v put a rotary on a tc1

essential - no, but it's nice to have for extra modes.
tc1 has issues btw, you want to pull the 8pin mcu and replace it with a discrete 2 transistor circuit.
it controls the power - but has a habit of drawing current instead of sleeping - 100mA of current!

Ha, how many different models do you have?

I looked through some of this thread and some of the 277 page thread on eev and it seems that there's no perfect lcr at any price. I'm starting to thing having two might be the best option, I already have an lcr-t4, so maybe if I get a tc1 that can round out the collection.

The other LCR that seems interesting is the Highland M644 which has some specfic hardware for frequency counting.

From what I have read, you can reprogram the MCU on the TC1 so you don't have to replace it with 2 transistors. It's unfortunate that it comes with a case, but I can print a new one...

[stj]

Re: ESR meter upgrades

if it's a large button and not a 5mm one then a rotary fits the pads.
i'v put a rotary on a tc1

essential - no, but it's nice to have for extra modes.
tc1 has issues btw, you want to pull the 8pin mcu and replace it with a discrete 2 transistor circuit.
it controls the power - but has a habit of drawing current instead of sleeping - 100mA of current!

[clearchris]

Re: ESR meter upgrades

How essential is a rotary encoder to the software? I understood that it was pretty important to navigate the menus, and both meters with enough flash to support all the functions (hiland) and tc-1 have only a button.

[eccerr0r]

Re: ESR meter upgrades

One would hope that they are, though for like microprocessors there's a reason most computers have a huge variance between them despite being the "same" frequency...

[stj]

Re: ESR meter upgrades

it's assumed you have a decent crystal and a good pcb track layout.
most crystals are 20ppm or better now, and variance in smd caps is very low.

[eccerr0r]

Re: ESR meter upgrades

How does one calibrate the crystal or is it dependent on the crystal being accurate? Can crystal errors be calibrated to some NIST traceable source?

[stj]

Re: ESR meter upgrades

it's 100% crystal.
that's one of the reasons why you do the cal procedure.

[eccerr0r]

Re: ESR meter upgrades

And how accurate is the crystal or is it using the on-chip oscillator, that thing really should be calibrated too...not sure if atmel^H^H^H^H^H^H microchip tunes those to 1ppm?