Dallas DS1486 and DS1250 Replacement designs

[picburner]

This is the correct header for those holes.

[whatboy]

Thank you very much!!!

[VE2JFQ]

hello, i have a problem with a ds1286 real time clock. i am a telecom technician, i have 3 ifr com-120b. all three the ds1286 battery has died! i managed to find three ds1286 in montreal, my problem is that i want to read and program them. i'm not a programmer, but i have a tl866 2 plus, but it doesn't take ds1286 or ds1284 (which contains 50bits of data. like time clock, serial number and options. i'm thinking of taking a pic programmer or arduino. I don't know these are two programs! what do you suggest to me? thank you and good day jacques

[Rasz]

battery died - nv ram is empty ram

[Tantratron]

hello, i have a problem with a ds1286 real time clock. i am a telecom technician, i have 3 ifr com-120b. all three the ds1286 battery has died! i managed to find three ds1286 in montreal, my problem is that i want to read and program them. i'm not a programmer, but i have a tl866 2 plus, but it doesn't take ds1286 or ds1284 (which contains 50bits of data. like time clock, serial number and options. i'm thinking of taking a pic programmer or arduino. I don't know these are two programs! what do you suggest to me? thank you and good day jacques

What test equipment are coming your DS1486 ?

[VE2JFQ]

it's not a ds1486 it's a ds1286. this is a telecom test set. com-120b manufactured by ifr. ifr no longer supports com-120b

[Ian.M]

VE2JFQ multiposted the above (#27) query.  The original thread is here:
https://www.eevblog.com/forum/programming/watchdog-programming-ds1286-and-others-need-help/

[Insatman]

I have built both boards using recommended components.  The DS1250 programmed and works just fine using my GQ-4x4 programmer.   I built two and tested them in my TDS784D.  The problem is trying to program the DS1486 replacement boards.  Again I built two and both refuse to program.   I also bought two of the Chinese copies from UT-Source and these program and work just fine in the 784D.  Since the GQ-4x4 does not support the DS1486, I have been using the DS1245 setting.  This seemed to work ok on the Chinese chips with the exception of verification errors.  I had assumed these were from the RTC bytes having changed.   Again both Chinese chips work just fine in the 784 with no test errors and all original scope options preserved.   My question is how to program the DS1486 replacement chips?   Can it be done with a GQ-4x4?  If so with what settings?

Some details.  The Dallas 1384G ICs were purchased from the recommended source in TX.   All other parts were ordered from Digikey with the exceptions of the batteries as DigiKey will not ship them internationally.   Instead I used coin battery holders and purchased batteries locally.  The coin holders require a bit of pin bending as the spacing is slightly different from the PCB layout, but only 50 mills, so easy to bent to fit.

The Chinese chips are marked with 2015 and 2016 date codes.  Since Dallas stopped making these chips in 2009 they must be clones or refurbished. 

In first photo top row are Chinese chips, next are original from 784D, bottom row are replacement designs.
2nd photo shows Working Chinese DS1486 and replacement DS1250 in 784D.
The Chinese chips were sold as used, but appear new.  The lead spacing is a bit off on the 1486 parts, but I was able to push them into a mill-max machined socket with a little persuasion.   

[Tantratron]

I have built both boards using recommended components.  The DS1250 programmed and works just fine using my GQ-4x4 programmer.   I built two and tested them in my TDS784D.  The problem is trying to program the DS1486 replacement boards...  Since the GQ-4x4 does not support the DS1486, I have been using the DS1245 setting...   My question is how to program the DS1486 replacement chips?   Can it be done with a GQ-4x4?  If so with what settings?

It is straightforward if installing both new DS replicas on the logic A11 board of your TDS784D (your TDS oscilloscope becomes the programmer). I recommend you first solder two 32 pins sockets on the PCB, after you plug your DS1486 and DS1250Y replica into the sockets. Then dumping (old NVRAMs) and writing the NVRAM's (replicas), the firmware thanks to a Github repo compilation https://github.com/ragges/tektools where in my case, I've used my MacBook Air and a GPIB-USB from National Instruments. For instance, I've used and found very practical the tekfwtool tool, again with MacOS where it was seamless and easy which should run easy with Windows, Linux...

[Insatman]

It is straightforward if installing both new DS replicas on the logic A11 board of your TDS784D (your TDS oscilloscope becomes the programmer). I recommend you first solder two 32 pins sockets on the PCB, after you plug your DS1486 and DS1250Y replica into the sockets. Then dumping (old NVRAMs) and writing the NVRAM's (replicas), the firmware thanks to a Github repo compilation https://github.com/ragges/tektools where in my case, I've used my MacBook Air and a GPIB-USB from National Instruments. For instance, I've used and found very practical the tekfwtool tool, again with MacOS where it was seamless and easy which should run easy with Windows, Linux...

Unfortuately I do not own an NI GPIB-USB unit.  I have an HP unit which I have been unable to get to work with the tektool software.

[Tantratron]

Well from what I've read here or in tektronix forum, it will tricky or catch 22 or chicken and egg situation to properly write the DS1486 via an external programmer. The first 20 bytes or more seems to have a specific protection or whatever affecting some external writing devices which is why I did prefer to invest into GPIB-US from NI then tektools which are open sourced.

By the way, did you dump (read) the content of both DS1486 and DS1250Y prior desoldering them from the A11 board ?

[Insatman]

Well from what I've read here or in tektronix forum, it will tricky or catch 22 or chicken and egg situation to properly write the DS1486 via an external programmer. The first 20 bytes or more seems to have a specific protection or whatever affecting some external writing devices which is why I did prefer to invest into GPIB-US from NI then tektools which are open sourced.

By the way, did you dump (read) the content of both DS1486 and DS1250Y prior desoldering them from the A11 board ?

It's interesting to note that I was able to write to the Chinese clone DS1486 just fine using the external programmer but that the replacement version gives an immediate error message.

I tried using the floppy dump utility prior to desoldering the original chips.  I got a file but have never used it.  Once the chips were desoldered, I was able to read them on the GQ-4x4 easily.  I used the DS1245 profile for the DS1486.   My 784D had DS1250 rather than the DS1650 some others have.   I had purchased DS1650 ICs.  So I read the original DS1250 with that profile and wrote the data to the DS1650 profile to the Chinese close chips.   I've tested all four of the Chinese chips and they work just fine in the scope (2x DS1486 and 2x DS1250).  Also the DS1250 replacement chips work as well.

[Tantratron]

Oups... you're very right where the other method I've totally forgot to suggest was the floppy disk (member @FLYTE utilities). I tend to not use it because I prefer the GPIB-USB with tekfwtool (member @SVEN utilities) but have you then tried writing the DS1486 and DS1250 replicas of @Cuebus member via the Floppy method ?

[Insatman]

Oups... you're very right where the other method I've totally forgot to suggest was the floppy disk (member @FLYTE utilities). I tend to not use it because I prefer the GPIB-USB with tekfwtool (member @SVEN utilities) but have you then tried writing the DS1486 and DS1250 replicas of @Cuebus member via the Floppy method ?

Well, I have a problem that prevents both methods (GPIB and floppy).  Turns out the 784D refuses to boot with the replica DS1486 installed.  The sequence gets stuck with the numeric display displaying two digits alternately forever.  Once I replace the replica DS1486 with either the original  or clone DS1486, the scope boots normally.

[Tantratron]

If you're certain that your PCB etching, your soldering and your chipset are correct then maybe the reason or a clue could be related to the fact your TDS784D runs with firmware 7.X version. I say this because most replication so far were done by C serie TDSxxx model (version 5.x) plus D series TDS do have two type of A11 and A10 boards non compatible where either you use 6.x firmwares or 7.x firmwares.

[madao]

DS1486 with wrong image shouldn't stopped  booting .   Firmware status doesn't matter.  Unit refuse to starting, if  NVSRAM is dead or away.
possible: dead IC or bad solder joint or contact issuses of DS1486 replica is causes of failure.

I own modded  TDS784D (FW7.3) with DS1486 replica. No issuses.  But  i have  one DS1384 with DOA. Unit starting with him, but extremely high battery consumption and Clock doesn't run... gnarf!

[Ian.M]

If you don't find any obvious dry joints or bridges on the DS1486 module with good lighting and decent magnification, IMHO you've reached the point where you need to be able to functionally test it.

 e.g. Use an Anduino Mega (or other 5V Arduino with enough I/O pins) and the DS1486 module in a breadboard, with the Vcc supply to it fed via two diodes + a pulldown resistor, with a shorting link across the diodes for normal operation, removed to test its write-protect mode.  Write a sketch to repeatedly dump the RTC + let you change any RTC register, and write another one that tests the RAM, looking for stuck data and address lines and stuck bits.  Hint: 1K series resistors in each data line make bus contention non-hazardous if you make a mistake coding the sketches transitions between reading and writing the data bus.

[Insatman]

DS1486 with wrong image shouldn't stopped  booting .   Firmware status doesn't matter.  Unit refuse to starting, if  NVSRAM is dead or away.
possible: dead IC or bad solder joint or contact issues of DS1486 replica is causes of failure.

I own modded  TDS784D (FW7.3) with DS1486 replica. No issues.  But  i have  one DS1384 with DOA. Unit starting with him, but extremely high battery consumption and Clock doesn't run... gnarf!

Yes I had heard that the 784D should have booted even without the DS1486 replica being programmed.  So something must be wrong.  I built two examples and both exhibit the same behavior, both in the programmer and the 784D.   Note when I attempt to boot the 784 the numeric display oscillates between 6 and 8, if that means anything.

so...I could have two bad DS1384 (bought from Specialty Electronics in TX, USA)...not likely.   Both boards could have an identical or similar construction fault...most likely.   

I will de-solder the battery holders on both PCBs and give them a through inspection.   

In the meantime, the 784D is working fine and passed SPC today.   I plan on replacing the hard-drive with a compact-flash drive as soon as I can obtain parts and transfer the disc image.  The present hard drive was made in 1998 and I'm nervous about how long it will last.    The CRT was replaced with a color LCD kit a couple of years back and the floppy drive was replaced with a USB floppy emulator at that time.

[james_s]

Yes I had heard that the 784D should have booted even without the DS1486 replica being programmed.  So something must be wrong.  I built two examples and both exhibit the same behavior, both in the programmer and the 784D.   Note when I attempt to boot the 784 the numeric display oscillates between 6 and 8, if that means anything.

That sounds like the DS1486 is in test mode. This causes one of the pins to oscillate at a frequency, 512hz IIRC to allow you to measure the frequency of the internal crystal. This will of course result in unpredictable behavior of whatever device it is installed in. I ran into this some time back when I was trying to program a similar Dallas RTC in a regular EPROM/flash programmer. Read the datasheet and it explains how to enable and disable test mode, I ended up using an arduino mega and wrote a little program to do it.

[Insatman]

Yes I had heard that the 784D should have booted even without the DS1486 replica being programmed.  So something must be wrong.  I built two examples and both exhibit the same behavior, both in the programmer and the 784D.   Note when I attempt to boot the 784 the numeric display oscillates between 6 and 8, if that means anything.

That sounds like the DS1486 is in test mode. This causes one of the pins to oscillate at a frequency, 512hz IIRC to allow you to measure the frequency of the internal crystal. This will of course result in unpredictable behavior of whatever device it is installed in. I ran into this some time back when I was trying to program a similar Dallas RTC in a regular EPROM/flash programmer. Read the datasheet and it explains how to enable and disable test mode, I ended up using an arduino mega and wrote a little program to do it.

The replica DS1486 is based on the DS1384G.   Looking at the datasheet of the DS1384G, I cannot find any mention of a test mode.

[Insatman]

I desoldered on of the battery holders on each of the two DS1486 replica units.  This was done to be able to uncover and inspect the DS1384G IC solder joints.   I did find one definite solder bridge on one unit.  I found a few other possible shorts on both units and cleaned up everything I saw.  Since the datasheet for the DS1384G says to ground the unused battery input if only one was used, I did that.

Behavior in the Eprom programmer was unchanged.  The IC can be read or verified as blank as a DS1245.  The IC cannot be written however and immediately generates an error code.  Both units behave the same. 

Behavior in the 784D is also unchanged.  The 784D does not boot and the numeric display oscillates between "6" and "8".   The scope behaves the same way if the DS1486 socket is empty.   Upon installation of the original or Chinese copy DS1486, the 784D works normally.

Maybe I just have two bad DS1384G?   Either originally or I killed them during soldering.   

[james_s]

Yes I had heard that the 784D should have booted even without the DS1486 replica being programmed.  So something must be wrong.  I built two examples and both exhibit the same behavior, both in the programmer and the 784D.   Note when I attempt to boot the 784 the numeric display oscillates between 6 and 8, if that means anything.

That sounds like the DS1486 is in test mode. This causes one of the pins to oscillate at a frequency, 512hz IIRC to allow you to measure the frequency of the internal crystal. This will of course result in unpredictable behavior of whatever device it is installed in. I ran into this some time back when I was trying to program a similar Dallas RTC in a regular EPROM/flash programmer. Read the datasheet and it explains how to enable and disable test mode, I ended up using an arduino mega and wrote a little program to do it.

The replica DS1486 is based on the DS1384G.   Looking at the datasheet of the DS1384G, I cannot find any mention of a test mode.

From the DS1384 datasheet: "SQW - Square Wave (output): This pin can be programmed to output a 1024 Hz square wave signal.
When the signal is turned off, the pin is high Z."

On the DS1486 this is shared with the /INTA pin. Have you tried scoping the pins to see if one has a square wave on it?

[Insatman]

Yes I had heard that the 784D should have booted even without the DS1486 replica being programmed.  So something must be wrong.  I built two examples and both exhibit the same behavior, both in the programmer and the 784D.   Note when I attempt to boot the 784 the numeric display oscillates between 6 and 8, if that means anything.

That sounds like the DS1486 is in test mode. This causes one of the pins to oscillate at a frequency, 512hz IIRC to allow you to measure the frequency of the internal crystal. This will of course result in unpredictable behavior of whatever device it is installed in. I ran into this some time back when I was trying to program a similar Dallas RTC in a regular EPROM/flash programmer. Read the datasheet and it explains how to enable and disable test mode, I ended up using an arduino mega and wrote a little program to do it.

The replica DS1486 is based on the DS1384G.   Looking at the datasheet of the DS1384G, I cannot find any mention of a test mode.

From the DS1384 datasheet: "SQW - Square Wave (output): This pin can be programmed to output a 1024 Hz square wave signal.
When the signal is turned off, the pin is high Z."

On the DS1486 this is shared with the /INTA pin. Have you tried scoping the pins to see if one has a square wave on it?

I have checked pin 30 on the DS1486 replica and got nothing but a little noise.  I do see 32kHz on the crystal, so at least that is working.

[cuebus]

Hi Insatman,

I'm the designer of this replacement. I figured I would give some insight of things I've run across having built a number of these now.
a) you did mention that you had solder bridges that you fixed after already testing them. You likely already fried the chips at this point. I can't say for sure which pins would or wouldn't cause the chip to die but my first build I also had a solder bridge and the chip was dead.
I also had an issue earlier this year with some flux that was highly conductive without me realizing it, and fried a number of chips during testing because I've usually tested before washing to avoid having to wash twice if I have to do any rework.

b)Ever since I switched to a solder paste workflow I've had none of the aformentioned issues and I highly suggest if people have the tools to use solder paste with standard QFP and TSSOP stencils. If you're using external flux, you have to make sure that the board is absolutely spotless. This is hard to do with flux that gets under the chips unless you have an ultrasonic cleaner.

c)Lastly I'm not sure how you're programming these, but I've found the TL866 (which is most people's go-to cheap programmer) extremely unreliable with the DS1486 in DS1245 mode. I really don't know what the cause is of the issue but I find often that data at the beginning of the chip is unable to be read correctly meaning if you try to make a binary dump of the data, you better be sure you don't have a bunch of FF in the first 0-100 rows. Each read tends to give me a different amount of data, yet the chips work fine in my scope, including the clock which is the first row of data. I have a theory that the TL866 might be trying to read the data too quickly after applying power. It looks like the DS1245 has a startup time of 125ms while the DS1486 is 200ms. I need to see if I can apply 5V externally without damaging the programmer to test this theory. I suppose I could lift the power pin to try that.

I recommend using the tektool or tekfwtool process that has been documented on this forum reasonably well.

Hope this helps you and anyone else working on this.

Yes I had heard that the 784D should have booted even without the DS1486 replica being programmed.  So something must be wrong.  I built two examples and both exhibit the same behavior, both in the programmer and the 784D.   Note when I attempt to boot the 784 the numeric display oscillates between 6 and 8, if that means anything.

That sounds like the DS1486 is in test mode. This causes one of the pins to oscillate at a frequency, 512hz IIRC to allow you to measure the frequency of the internal crystal. This will of course result in unpredictable behavior of whatever device it is installed in. I ran into this some time back when I was trying to program a similar Dallas RTC in a regular EPROM/flash programmer. Read the datasheet and it explains how to enable and disable test mode, I ended up using an arduino mega and wrote a little program to do it.

The replica DS1486 is based on the DS1384G.   Looking at the datasheet of the DS1384G, I cannot find any mention of a test mode.

From the DS1384 datasheet: "SQW - Square Wave (output): This pin can be programmed to output a 1024 Hz square wave signal.
When the signal is turned off, the pin is high Z."

On the DS1486 this is shared with the /INTA pin. Have you tried scoping the pins to see if one has a square wave on it?

I have checked pin 30 on the DS1486 replica and got nothing but a little noise.  I do see 32kHz on the crystal, so at least that is working.

[Tantratron]

I built a pair using the PCBs posted here, I had a brain fart and installed a chip backwards on both of them but noticed the error and flipped it around before I tried applying power. In the end both worked perfectly, along with the backup and restore scripts and my scope is working perfectly with the replacements. I got the RTC chip from a China seller, I was concerned it might be a fake but it works fine so I think it's the real deal.

Hi James, what method to program both replicas have you used ?