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Re: Low cost, OSSW/OSHW AR488 GPIB-USB adapter

 

开云体育

We need to move the FOGA development discussion to a new thread.

DaveD

Sent from a small flat thingy

On Jul 25, 2019, at 12:49, Dave_G0WBX via Groups.Io <g8kbvdave@...> wrote:

Re:-

An Altera Max 2 series part (3.3V), mounted on a PC board along with a clock oscillator and 5V to 3.3V voltage regulator would be a good start.
EPM240 series along with a USB Blaster programmer for about $12

THAT does look interesting.?? Thanks for the pointer.

Cheers.

Dave.


-- 
Created on and sent from a Unix like PC running and using free and open source software:

Re: Low cost, OSSW/OSHW AR488 GPIB-USB adapter

 

开云体育

Re:-

An Altera Max 2 series part (3.3V), mounted on a PC board along with a clock oscillator and 5V to 3.3V voltage regulator would be a good start.
EPM240 series along with a USB Blaster programmer for about $12

THAT does look interesting.?? Thanks for the pointer.

Cheers.

Dave.


-- 
Created on and sent from a Unix like PC running and using free and open source software:

Re: Low cost, OSSW/OSHW AR488 GPIB-USB adapter

 

That's good to know. Thanks.

On 7/25/2019 12:01 PM, Chuck Harris wrote:
Lattices ICE-40 is fully supported using open source verilog
tools, and the open source ICEStorm synthesis tool, and the
open source Yosys fitter... It's an excellent little, very
low power, reprogrammable FPGA, available in 1K through 80K
versions. It works very well.

-Chuck Harris

Dave Daniel wrote:
Also, don’t foget issues of cost of buying and/or finding “free” Verilog/VHDL copiler/synthesis and simulation tools.

DaveD
Re: Low cost, OSSW/OSHW AR488 GPIB-USB adapter

 

Lattices ICE-40 is fully supported using open source verilog
tools, and the open source ICEStorm synthesis tool, and the
open source Yosys fitter... It's an excellent little, very
low power, reprogrammable FPGA, available in 1K through 80K
versions. It works very well.

-Chuck Harris

Dave Daniel wrote:

Also, don’t foget issues of cost of buying and/or finding “free” Verilog/VHDL copiler/synthesis and simulation tools.

DaveD
Re: Low cost, OSSW/OSHW AR488 GPIB-USB adapter

 

On 7/25/2019 11:00 AM, Dave Daniel wrote:
And I forgot to list the cost of the FPGA vendor’s development suite (e.g., Xilinx’s Vivado) which used to cost money.
Vivado doesn't support the "older" chips, but only the higher end BGA chips, which I remember at a minimum cost of at least 30 dollars).

ISE web edition supports the older chips, but you may want two versions depending on what chips you support (the one for win 10 is limited).

ISE has a simulator, compiler, etc.

Harvey


Sent from a small flat thingy

On Jul 25, 2019, at 10:58, Dave Daniel <kc0wjn@...> wrote:

Also, don’t foget issues of cost of buying and/or finding “free” Verilog/VHDL copiler/synthesis and simulation tools.

DaveD

Sent from a small flat thingy

On Jul 25, 2019, at 10:08, Harvey White <madyn@...> wrote:


On 7/25/2019 12:58 AM, John kolb wrote:

CPLD's are less complex than FPGA's but not necessarily cheaper as the newer design parts get a lot more logic in a lot less silicon, at the cost of using lower voltages.
Xilinx. 32 cell = 1.50, 64 cell = 3.25, 128 cell = 7.00, 256 cell = 15 dollars

Spartan 3AN (built in eeprom) 50K gates, about 14 dollars.

Spartan 6, (no eeprom, use winbond = 0.75) about 12 dollars, well over 50 K gates, has a 16 dollar pin compatible version with twice capacity.

Have standardized on the Spartan 6.

Pay careful attention to the bypass capacitors and clock run out to the configuration eeprom. Programmer available through amazon, web edition (local compile, report back to daddy) is free.

3.3 volts but then again was using them with Xmega and now with ARM.

All chips in non-BGA versions, TQFP-144, so therefore solderable.

SPI interface available through open cores, suggest register structure with read/write registers and go from there.

(and yes, done that....)

Harvey

Lattice 7000S series parts were good for a 5V part, but no longer available new, although still plenty on ebay.

An Altera Max 2 series part (3.3V), mounted on a PC board along with a clock oscillator and 5V to 3.3V voltage regulator would be a good start.
EPM240 series along with a USB Blaster programmer for about $12


Similar modules are available for other CPLDs and FPGAs if the logic doesn't fit the EPM240.

Using a premade module gets one away from having to deal with surface mount parts, at least as long as the interface IC's are still available as thru-hole parts.

I'm still hoping I can figure out how to use the UGPlus to talk to my HP 3456.

John


On 7/24/2019 1:12 PM, Harvey White wrote:

On 7/24/2019 2:01 PM, saipan59 wrote:
I once did a design that had the upD7210 in it (includes controller), driven by an XMEGA. I've got a similar design (unproven yet) that is driven by an ARM processor. Since the 75160/75162 are readily available (or at least, were....) I'd stick with them. I also have a possibility of using an FPGA to do the same. I'd stick with the FPGA for a new design since it can always be tweaked. I suspect that a CPLD may be too expensive for the complexity needed at that level.

FPGA goes through level shifters to the 488 bus drivers, so it's all well protected.

After I do a bunch of software (OS/graphics redesign) that's on the list (it says here......)

Harvey
Re: What would you do if you had some test equipment with Serial No: 0000001?

 

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Dear All,

Yes it’s interesting how R&S and Keysight go up and down in their older equipment repair policies.

There was a time when R&S would repair even very elderly kit for us, whereas post 2001 bubble Agilent as they then were really annoyed us by dropping support for rather grandiose systems which we had paid them six figure sums for.

We bought more R&S as a result.

More recently Keysight have been really quite helpful in repairing older equipment whereas R&S are being less so; this will be a factor in an acquisition I’m currently running.

What really annoys me is the lack of support of equipment which uses older versions of Windows- knowing the policies of that company, I now insist on hearing how long term support will be assured before I buy.

Regards,

Alwyn


_____________________________________________________

Alwyn Seeds, Director
SynOptika Ltd.,
114 Beaufort Street,
London,
SW3 6BU,
England.

Tel.: +44 (0) 20 7376 4110


SynOptika Ltd., Registered in England and Wales: No. 04606737
Registered Office: 114 Beaufort Street, London, SW3 6BU, United Kingdom.
_____________________________________________________
Re: Low cost, OSSW/OSHW AR488 GPIB-USB adapter

 

The TMS9914 made a fine controller. I know because I designed them into
PC-XT GPIB controller cards. Like everything I have ever used, you had to
put some of the higher level logic into your drivers... and a little glue
logic here and there... It was all discussed in ti's apnotes.

-Chuck Harris

Harvey White wrote:


On 7/25/2019 12:56 AM, Kevin Oconnor wrote:
@Harvey
Good u brought up the upD7210. If that’s the chip I’m thinking of, it is a complete
HPIB interface device capable of driving the full complement bus devices.
I think they're barely available. I've gotten mine out of older instruments that
were non functional. (not HP/Fluke/etc....) The TMS9914 was only a talker/listener,
the 68488 was full. NI supposedly still sells them, but some companies have been
touting their FPGA solution to the problem. There's an HPIB
controller/listener/talker implementation at opencores.org that I've downloaded, and
Re: Low cost, OSSW/OSHW AR488 GPIB-USB adapter

 

And I forgot to list the cost of the FPGA vendor’s development suite (e.g., Xilinx’s Vivado) which used to cost money.

Sent from a small flat thingy

On Jul 25, 2019, at 10:58, Dave Daniel <kc0wjn@...> wrote:

Also, don’t foget issues of cost of buying and/or finding “free” Verilog/VHDL copiler/synthesis and simulation tools.

DaveD

Sent from a small flat thingy

On Jul 25, 2019, at 10:08, Harvey White <madyn@...> wrote:


On 7/25/2019 12:58 AM, John kolb wrote:

CPLD's are less complex than FPGA's but not necessarily cheaper as the newer design parts get a lot more logic in a lot less silicon, at the cost of using lower voltages.
Xilinx. 32 cell = 1.50, 64 cell = 3.25, 128 cell = 7.00, 256 cell = 15 dollars

Spartan 3AN (built in eeprom) 50K gates, about 14 dollars.

Spartan 6, (no eeprom, use winbond = 0.75) about 12 dollars, well over 50 K gates, has a 16 dollar pin compatible version with twice capacity.

Have standardized on the Spartan 6.

Pay careful attention to the bypass capacitors and clock run out to the configuration eeprom. Programmer available through amazon, web edition (local compile, report back to daddy) is free.

3.3 volts but then again was using them with Xmega and now with ARM.

All chips in non-BGA versions, TQFP-144, so therefore solderable.

SPI interface available through open cores, suggest register structure with read/write registers and go from there.

(and yes, done that....)

Harvey


Lattice 7000S series parts were good for a 5V part, but no longer available new, although still plenty on ebay.

An Altera Max 2 series part (3.3V), mounted on a PC board along with a clock oscillator and 5V to 3.3V voltage regulator would be a good start.
EPM240 series along with a USB Blaster programmer for about $12


Similar modules are available for other CPLDs and FPGAs if the logic doesn't fit the EPM240.

Using a premade module gets one away from having to deal with surface mount parts, at least as long as the interface IC's are still available as thru-hole parts.

I'm still hoping I can figure out how to use the UGPlus to talk to my HP 3456.

John


On 7/24/2019 1:12 PM, Harvey White wrote:

On 7/24/2019 2:01 PM, saipan59 wrote:
I once did a design that had the upD7210 in it (includes controller), driven by an XMEGA. I've got a similar design (unproven yet) that is driven by an ARM processor. Since the 75160/75162 are readily available (or at least, were....) I'd stick with them. I also have a possibility of using an FPGA to do the same. I'd stick with the FPGA for a new design since it can always be tweaked. I suspect that a CPLD may be too expensive for the complexity needed at that level.

FPGA goes through level shifters to the 488 bus drivers, so it's all well protected.

After I do a bunch of software (OS/graphics redesign) that's on the list (it says here......)

Harvey
Re: Low cost, OSSW/OSHW AR488 GPIB-USB adapter

 

Also, don’t foget issues of cost of buying and/or finding “free” Verilog/VHDL copiler/synthesis and simulation tools.

DaveD

Sent from a small flat thingy

On Jul 25, 2019, at 10:08, Harvey White <madyn@...> wrote:


On 7/25/2019 12:58 AM, John kolb wrote:

CPLD's are less complex than FPGA's but not necessarily cheaper as the newer design parts get a lot more logic in a lot less silicon, at the cost of using lower voltages.
Xilinx. 32 cell = 1.50, 64 cell = 3.25, 128 cell = 7.00, 256 cell = 15 dollars

Spartan 3AN (built in eeprom) 50K gates, about 14 dollars.

Spartan 6, (no eeprom, use winbond = 0.75) about 12 dollars, well over 50 K gates, has a 16 dollar pin compatible version with twice capacity.

Have standardized on the Spartan 6.

Pay careful attention to the bypass capacitors and clock run out to the configuration eeprom. Programmer available through amazon, web edition (local compile, report back to daddy) is free.

3.3 volts but then again was using them with Xmega and now with ARM.

All chips in non-BGA versions, TQFP-144, so therefore solderable.

SPI interface available through open cores, suggest register structure with read/write registers and go from there.

(and yes, done that....)

Harvey


Lattice 7000S series parts were good for a 5V part, but no longer available new, although still plenty on ebay.

An Altera Max 2 series part (3.3V), mounted on a PC board along with a clock oscillator and 5V to 3.3V voltage regulator would be a good start.
EPM240 series along with a USB Blaster programmer for about $12


Similar modules are available for other CPLDs and FPGAs if the logic doesn't fit the EPM240.

Using a premade module gets one away from having to deal with surface mount parts, at least as long as the interface IC's are still available as thru-hole parts.

I'm still hoping I can figure out how to use the UGPlus to talk to my HP 3456.

John


On 7/24/2019 1:12 PM, Harvey White wrote:

On 7/24/2019 2:01 PM, saipan59 wrote:
I once did a design that had the upD7210 in it (includes controller), driven by an XMEGA. I've got a similar design (unproven yet) that is driven by an ARM processor. Since the 75160/75162 are readily available (or at least, were....) I'd stick with them. I also have a possibility of using an FPGA to do the same. I'd stick with the FPGA for a new design since it can always be tweaked. I suspect that a CPLD may be too expensive for the complexity needed at that level.

FPGA goes through level shifters to the 488 bus drivers, so it's all well protected.

After I do a bunch of software (OS/graphics redesign) that's on the list (it says here......)

Harvey
Re: What would you do if you had some test equipment with Serial No: 0000001?

 

开云体育

R&S has some amazing gear but I have avoided it due to unrepairability, lack of service manuals, and lack of support of the older units.?

Anotherwords, it’s great until it breaks, then it’s worthless.?


Peter

On Jul 25, 2019, at 10:17 AM, Jim Ford <james.ford@...> wrote:

Hi, Danny.

R&S could be more of a wet dream than HP, depending on the model!

Back at the late, great Powerwave in the early 2000's, HP/Agilent spectrum analyzers were on most engineers' benches, but the R&S units were few and far between, due to the cost.

Same at Broadcom (2006 to 2016) during my stint there, come to think of it.

Jim Ford



Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------
From: DANIEL RAFFERTY <daniel1967@...>
Date: 7/25/19 7:04 AM (GMT-08:00)
Subject: [HP-Agilent-Keysight-equipment] What would you do if you had some test equipment with Serial No: 0000001?

Hello All

I don't often post to the list, but I do read its traffic with interest :-)

It's not a piece of HP test equipment before anyone has a "wet dream".
Its a piece of Rhode & Schwarz test equipment that I rescued from a skip
which was destined to go to landfill.

By rights I shouldn't have done it, but I managed to get permission from
my line manager to take it away as there was nothing classified about
it. That organisations policy was everthing gets crushed and dropped
into a landfill,? rather than relieve the bruden on the tax payers and
sell expensive usable test equiment onto small businesses and private
individuals.

It still works, but its MMI has a few bugs and I was thinking of putting
on Ebay (my head says Yes!).
But my heart says I should hold onto it, as its a rare beast.

Best Regards

Danny G7TTR
Re: What would you do if you had some test equipment with Serial No: 0000001?

 

开云体育

Hi, Danny.

R&S could be more of a wet dream than HP, depending on the model!

Back at the late, great Powerwave in the early 2000's, HP/Agilent spectrum analyzers were on most engineers' benches, but the R&S units were few and far between, due to the cost.

Same at Broadcom (2006 to 2016) during my stint there, come to think of it.

Jim Ford



Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------
From: DANIEL RAFFERTY <daniel1967@...>
Date: 7/25/19 7:04 AM (GMT-08:00)
Subject: [HP-Agilent-Keysight-equipment] What would you do if you had some test equipment with Serial No: 0000001?

Hello All

I don't often post to the list, but I do read its traffic with interest :-)

It's not a piece of HP test equipment before anyone has a "wet dream".
Its a piece of Rhode & Schwarz test equipment that I rescued from a skip
which was destined to go to landfill.

By rights I shouldn't have done it, but I managed to get permission from
my line manager to take it away as there was nothing classified about
it. That organisations policy was everthing gets crushed and dropped
into a landfill,? rather than relieve the bruden on the tax payers and
sell expensive usable test equiment onto small businesses and private
individuals.

It still works, but its MMI has a few bugs and I was thinking of putting
on Ebay (my head says Yes!).
But my heart says I should hold onto it, as its a rare beast.

Best Regards

Danny G7TTR
Re: Low cost, OSSW/OSHW AR488 GPIB-USB adapter

 

On 7/25/2019 12:58 AM, John kolb wrote:

CPLD's are less complex than FPGA's but not necessarily cheaper as the newer design parts get a lot more logic in a lot less silicon, at the cost of using lower voltages.
Xilinx.? 32 cell = 1.50, 64 cell = 3.25, 128 cell = 7.00, 256 cell = 15 dollars

Spartan 3AN (built in eeprom) 50K gates, about 14 dollars.

Spartan 6, (no eeprom, use winbond = 0.75) about 12 dollars, well over 50 K gates, has a 16 dollar pin compatible version with twice capacity.

Have standardized on the Spartan 6.

Pay careful attention to the bypass capacitors and clock run out to the configuration eeprom.? Programmer available through amazon, web edition (local compile, report back to daddy) is free.

3.3 volts but then again was using them with Xmega and now with ARM.

All chips in non-BGA versions, TQFP-144, so therefore solderable.

SPI interface available through open cores, suggest register structure with read/write registers and go from there.

(and yes, done that....)

Harvey


Lattice 7000S series parts were good for a 5V part, but no longer available new, although still plenty on ebay.

An Altera Max 2 series part (3.3V), mounted on a PC board along with a clock oscillator and 5V to 3.3V voltage regulator would be a good start.
EPM240 series along with a USB Blaster programmer for about $12


Similar modules are available for other CPLDs and FPGAs if the logic doesn't fit the EPM240.

Using a premade module gets one away from having to deal with surface mount parts, at least as long as the interface IC's are still available as thru-hole parts.

I'm still hoping I can figure out how to use the UGPlus to talk to my HP 3456.

John


On 7/24/2019 1:12 PM, Harvey White wrote:

On 7/24/2019 2:01 PM, saipan59 wrote:
I once did a design that had the upD7210 in it (includes controller), driven by an XMEGA.? I've got a similar design (unproven yet) that is driven by an ARM processor.? Since the 75160/75162 are readily available (or at least, were....) I'd stick with them.? I also have a possibility of using an FPGA to do the same.? I'd stick with the FPGA for a new design since it can always be tweaked.? I suspect that a CPLD may be too expensive for the complexity needed at that level.

FPGA goes through level shifters to the 488 bus drivers, so it's all well protected.

After I do a bunch of software (OS/graphics redesign) that's on the list (it says here......)

Harvey
Re: Low cost, OSSW/OSHW AR488 GPIB-USB adapter

 

Hi John,

As I said, that was the maximum load instrument. When I first
started working with HPIB, it had just superseded the BCD interface.

My first implementation used 74LS, so my load was about 0.2 inputs,
in its worst case... which were the control lines.

Early instruments would crash the buss if they were turned off, due
to all of the pull down load.

Very soon it became apparent that folks wanted to string their entire
lab's worth of HPIB controlled instruments on their HPIB calculator/
computer, and not worry about whether they were on, or off... So the
lower loss interface drivers had to come out.

The termination resistors are 3K pu, and 6K pd to 5V, so a buss full
of inputs will be at roughly 66% of 5V, or 3.3V... probably a little
higher due to the input leakage currents.

-Chuck Harris

John kolb wrote:


The HP 3456 uses MC3448 IC's on all the GPIB lines. This IC is "high impedance"
during receive, and open collector and providing pullup conforming to IEEE 448 spec
during transmission.

I would expect most of the instruments owned by this group to present much less than
the 2 TTL loads, so bus loading probably not a problem.

I would wonder what the bus voltage floats to when EVERYONE is receiving.

Haven't dealt with GPIB since about 1970 when I designed a GPIB controlled switch box
for internal use at Wavetek. Needed many voltage readings to find the peak values
when generating 0.001 Hz with their function generators.

John

On 7/24/2019 3:12 PM, Chuck Harris wrote:
I can answer a couple of your points:

1) The maximum load any instrument is allowed to present onto the
buss is 2 standard TTL inputs. It was always recommended that
What would you do if you had some test equipment with Serial No: 0000001?

 

Hello All

I don't often post to the list, but I do read its traffic with interest :-)

It's not a piece of HP test equipment before anyone has a "wet dream".
Its a piece of Rhode & Schwarz test equipment that I rescued from a skip
which was destined to go to landfill.

By rights I shouldn't have done it, but I managed to get permission from
my line manager to take it away as there was nothing classified about
it. That organisations policy was everthing gets crushed and dropped
into a landfill, rather than relieve the bruden on the tax payers and
sell expensive usable test equiment onto small businesses and private
individuals.

It still works, but its MMI has a few bugs and I was thinking of putting
on Ebay (my head says Yes!).
But my heart says I should hold onto it, as its a rare beast.

Best Regards

Danny G7TTR
Re: Low cost, OSSW/OSHW AR488 GPIB-USB adapter

 

On 7/25/2019 1:34 AM, John kolb wrote:

The HP 3456 uses MC3448 IC's on all the GPIB lines. This IC is "high impedance" during receive, and open collector and providing pullup conforming to IEEE 448 spec during transmission.
Those are the open collector versions?

I would expect most of the instruments owned by this group to present much less than the 2 TTL loads, so bus loading probably not a problem.
but how many of them?


I would wonder what the bus voltage floats to when EVERYONE is receiving.
Resistive terminations.

Harvey



Haven't dealt with GPIB since about 1970 when I designed a GPIB controlled switch box for internal use at Wavetek. Needed many voltage readings to find the peak values when generating 0.001 Hz with their function generators.

John

On 7/24/2019 3:12 PM, Chuck Harris wrote:
I can answer a couple of your points:

1)? The maximum load any instrument is allowed to present onto the
???? buss is 2 standard TTL inputs.? It was always recommended that
???? the load be only 1 standard TTL input.? Implementations using
???? the TI drivers are much lower than that.

2)? The minimum drive capability (low) of any driver pin is 48ma.

3)? The bus has pull up resistors as well as pull down resistors.
???? I seem to recall 3K pull up, and 6.2K pull down... or maybe it
???? was the other way around...

The numbers work roughly as follows:

1 ttl input load (low) is 1.6ma, 2 is, of course, 3.2ma.

48ma / 3.2ma = 15 maximum, maximum load instruments on the bus at
any one time.

However, the recommendation was only 1 TTL load per input, which would
lead to 30 such instruments total as being the maximum you can drive.

Originally, the intended chips to do the driving were the 7438, which is
a quad NAND OC driver with 48ma per pin capability, and a 7404 as the input.

-Chuck Harris

Reginald Beardsley via Groups.Io wrote:
Hard to know where to begin.

Here is data about the Arduino Uno chip.? It operates from 1.8 to 5.5 V and can source 40 mA from a single pin and source and sink a total of 200 mA for the DIP package.? The SMT package can sink 400 mA.





The board I'm using drives the bus directly. so it probably would not be able to drive a fully populated bus.? The AR488 FW is limited to addresses 1-29 in controller mode.

My knowledge of IEEE-488 is limited to knowing what it is and that the C64 used? a serial implementation for the disk drive interface.? So I have no idea how much drive an instrument requires.? Looking at the SN75160 datasheet it's a bit hard for me to tell whether the ratings are for individual pins or all pins.

I have a total of 12-13 instruments with GPIB interfaces. I'm not sure about the LeCroy DDA-125 and it is much to hard to get to where I could tell by inspection what options it has.

Aside from investigating voltage reference aging and thermal hysteresis, my primary and possibly only application of GPIB would be automating an annual calibration run of my instruments.

I have no need of a cal lab certificate, and as various people have commented,? what cal labs actually do for your money is a bit questionable.? Ideally I'd like to be able to send a single device to a cal lab and then cal everything else to that.? Better still would be to get a traveling set of basic references once a year.

I've generally looked down my nose at the AVR chips, preferring the MSP430 and Stellaris lines from TI and the STM32Fx from ST.? But at $3 for a Chinese copy they look better all the time.

Reg
Re: Low cost, OSSW/OSHW AR488 GPIB-USB adapter

 

On 7/25/2019 12:56 AM, Kevin Oconnor wrote:
@Harvey
Good u brought up the upD7210. If that’s the chip I’m thinking of, it is a complete HPIB interface device capable of driving the full complement bus devices.
I think they're barely available.? I've gotten mine out of older instruments that were non functional.? (not HP/Fluke/etc....)? The TMS9914 was only a talker/listener, the 68488 was full.? NI supposedly still sells them, but some companies have been touting their FPGA solution to the problem.? There's an HPIB controller/listener/talker implementation at opencores.org that I've downloaded, and will one day try.
Fluke used it in the later versions GPIB PCBs for the 884X DMMs rather than the discrete design of the earlier boards. One could use the upD7210 with a micro or PI I suppose, and solve the # of units problem. (Is it still available?)
Not sure at all.? I've got a complete CPU board replacement for the Tek DM5010 in the works, which (due to 100 cm * 100 cm cheap Chinese discount board limitations) is built from two boards.? One of them is the 488 bus interface.? The design right now uses a upD7210, but could be reworked to use the original TMS9914 in the DMM itself.? Another option is simply to use the FPGA, which I can program.? Level shifting is on board, and the proper 488 bus drivers are also on board (Tek did use them).

One thing that can be done with that board is to make a single unit properly styled TM5000 plugin that's effectively a smart 488 bus controller with all the custom interfaces, wifi, NRF24L01, etc....? maybe....


Harvey


For me, I have a lot of GPIB units on my benches, and they are all tied to the bus and computer. I don’t want to think about climbing back there to connect up the 2-3 I want to use each time. That’s why the NI device.
Also, working with those old GPIB connectors is a real PITA! Only used cables are affordable, and they are often ratty with flaky or bent screws. If you stack them, you can never predict where they are going to separate! And try to find correct replacement screws, what a pain. (I did find a source recently). And what about the black/silver thread incompatibility! Anyway, I hated that connector in 1975. I still hate it today. Oops, dating myself.
Kevin

Sent from kjo iPhone
Re: Low cost, OSSW/OSHW AR488 GPIB-USB adapter

 

开云体育

Kevin, (and anybody else interested in using GPIB),

Check out www.ko4bb.com/getsimple/index.php?id=controlling-instruments-via-gpib

About 2/3 the way down the page it tells how to make your own inexpensive, lightweight GPIB cables.? I haven't tried it myself yet, but you know I have the page bookmarked!

Jim Ford?






Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------
From: Kevin Oconnor <kjo@...>
Date: 7/24/19 9:56 PM (GMT-08:00)
Subject: Re: [HP-Agilent-Keysight-equipment] Low cost, OSSW/OSHW AR488 GPIB-USB adapter

@Harvey
Good u brought up the upD7210. If that’s the chip I’m thinking of, it is a complete HPIB interface device capable of driving the full complement bus devices. Fluke used it in the later versions GPIB PCBs for the 884X DMMs rather than the discrete design of the earlier boards. One could use the upD7210 with a micro or PI I suppose, and solve the # of units problem. (Is it still available?)
For me, I have a lot of GPIB units on my benches, and they are all tied to the bus and computer. I don’t want to think about climbing back there to connect up the 2-3 I want to use each time. That’s why the NI device.
Also, working with those old GPIB connectors is a real PITA! Only used cables are affordable, and they are often ratty with flaky or bent screws. If you stack them, you can never predict where they are going to separate! And try to find correct replacement screws, what a pain. (I did find a source recently). And what about the black/silver thread incompatibility!? Anyway, I hated that connector in 1975. I still hate it today. Oops, dating myself.
Kevin

Sent from kjo iPhone
Re: Low cost, OSSW/OSHW AR488 GPIB-USB adapter

 

The HP 3456 uses MC3448 IC's on all the GPIB lines. This IC is "high impedance" during receive, and open collector and providing pullup conforming to IEEE 448 spec during transmission.

I would expect most of the instruments owned by this group to present much less than the 2 TTL loads, so bus loading probably not a problem.

I would wonder what the bus voltage floats to when EVERYONE is receiving.

Haven't dealt with GPIB since about 1970 when I designed a GPIB controlled switch box for internal use at Wavetek. Needed many voltage readings to find the peak values when generating 0.001 Hz with their function generators.

John

On 7/24/2019 3:12 PM, Chuck Harris wrote:
I can answer a couple of your points:
1) The maximum load any instrument is allowed to present onto the
buss is 2 standard TTL inputs. It was always recommended that
the load be only 1 standard TTL input. Implementations using
the TI drivers are much lower than that.
2) The minimum drive capability (low) of any driver pin is 48ma.
3) The bus has pull up resistors as well as pull down resistors.
I seem to recall 3K pull up, and 6.2K pull down... or maybe it
was the other way around...
The numbers work roughly as follows:
1 ttl input load (low) is 1.6ma, 2 is, of course, 3.2ma.
48ma / 3.2ma = 15 maximum, maximum load instruments on the bus at
any one time.
However, the recommendation was only 1 TTL load per input, which would
lead to 30 such instruments total as being the maximum you can drive.
Originally, the intended chips to do the driving were the 7438, which is
a quad NAND OC driver with 48ma per pin capability, and a 7404 as the input.
-Chuck Harris
Reginald Beardsley via Groups.Io wrote:
Hard to know where to begin.

Here is data about the Arduino Uno chip. It operates from 1.8 to 5.5 V and can source 40 mA from a single pin and source and sink a total of 200 mA for the DIP package. The SMT package can sink 400 mA.





The board I'm using drives the bus directly. so it probably would not be able to drive a fully populated bus. The AR488 FW is limited to addresses 1-29 in controller mode.

My knowledge of IEEE-488 is limited to knowing what it is and that the C64 used a serial implementation for the disk drive interface. So I have no idea how much drive an instrument requires. Looking at the SN75160 datasheet it's a bit hard for me to tell whether the ratings are for individual pins or all pins.

I have a total of 12-13 instruments with GPIB interfaces. I'm not sure about the LeCroy DDA-125 and it is much to hard to get to where I could tell by inspection what options it has.

Aside from investigating voltage reference aging and thermal hysteresis, my primary and possibly only application of GPIB would be automating an annual calibration run of my instruments.

I have no need of a cal lab certificate, and as various people have commented, what cal labs actually do for your money is a bit questionable. Ideally I'd like to be able to send a single device to a cal lab and then cal everything else to that. Better still would be to get a traveling set of basic references once a year.

I've generally looked down my nose at the AVR chips, preferring the MSP430 and Stellaris lines from TI and the STM32Fx from ST. But at $3 for a Chinese copy they look better all the time.

Reg
Re: Low cost, OSSW/OSHW AR488 GPIB-USB adapter

 

CPLD's are less complex than FPGA's but not necessarily cheaper as the newer design parts get a lot more logic in a lot less silicon, at the cost of using lower voltages.

Lattice 7000S series parts were good for a 5V part, but no longer available new, although still plenty on ebay.

An Altera Max 2 series part (3.3V), mounted on a PC board along with a clock oscillator and 5V to 3.3V voltage regulator would be a good start.
EPM240 series along with a USB Blaster programmer for about $12


Similar modules are available for other CPLDs and FPGAs if the logic doesn't fit the EPM240.

Using a premade module gets one away from having to deal with surface mount parts, at least as long as the interface IC's are still available as thru-hole parts.

I'm still hoping I can figure out how to use the UGPlus to talk to my HP 3456.

John

On 7/24/2019 1:12 PM, Harvey White wrote:
On 7/24/2019 2:01 PM, saipan59 wrote:
I once did a design that had the upD7210 in it (includes controller), driven by an XMEGA.? I've got a similar design (unproven yet) that is driven by an ARM processor.? Since the 75160/75162 are readily available (or at least, were....) I'd stick with them.? I also have a possibility of using an FPGA to do the same.? I'd stick with the FPGA for a new design since it can always be tweaked.? I suspect that a CPLD may be too expensive for the complexity needed at that level.
FPGA goes through level shifters to the 488 bus drivers, so it's all well protected.
After I do a bunch of software (OS/graphics redesign) that's on the list (it says here......)
Harvey
Re: Low cost, OSSW/OSHW AR488 GPIB-USB adapter

 

开云体育

Re:-

A truly great implementation would use a SBC, and something like TI's
SN75160/161/162BDWR GPIB driver set... which are still available, and do
have the capability to drive a full buss... Mouser has them, in stock.

But, alas, you won't be driving that chip set from most USB ports.

-Chuck Harris

Odd, because that's exactly what NI, Agilent/Keysight, Keithley do with their USB/GPIB adapters, that are powered from the host PC over the USB port.

Also..

As most, if not all, of the Arduino or Pic based USB/Serial to GPIB adapters are open source, code and schematic, it's relatively simple to add "proper" bus drivers if you needed.

The difficult bit, will be negotiating with the host PC, for it to allow enough current to be pulled from the USB port to power it all, if a "Full" GPIB system is ever connected...

No one, and I mean no one who knows SBC's like the Pi series or similar, would even consider connecting a GPIB bus to the GPIO pins, for one thing, GPIB is 5V, and the GPIO pins are 3V logic, some may be 5V tolerant, but even then that's not good practice.?? But there is no reason not to put some logic between it and some bus drivers, that use the full 5V to run the bus.

Many years back, I managed to crudely talk to one simple instrument (a MI power meter) by bit-banging the LPT port on a Win9x system to emulate a GPIB controler.?? Slow and fragile, but it worked.? (No, I don't have that code, or notes any more, it was a "just because I can" experiment that got a somewhat out of hand...)

No drivers were harmed.

Regards.

Dave B



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