A little while back, I salvaged these cards from boxes just outside of UNSW Electrical Engineering Room 201. Special thanks goes to Mr. Chris Lu for giving me permission to remove these and keep them.
AX5411 (specs from here)
- 60kHz 12bit ISA AD card
- 16SE channel
- 2*DA 12bit 0-5/10V
- 24/24 TTL IO
- programmable gain ±10V, ±5V, ±2.5V, ±1.25V, ±0.63V, ±0.32V
- with Basic, C & Pascal driver
- compatible DAS-16 (SE only)
- Windows and Unix-driver deliverable
Lets take a closer look at this card.
We can see an 8-bit ISA interface, suitable for earlier 286’s. There are DMA jumpers, and a set of DIP switches. There are many Motorola, Hitachi, National, and STMicroelectronics discrete DIP chips. All of the socketed chips seem to be the analog opamps, A/D converters, etc. There are a myriad of 10-turn precision potentiometers for calibration.
There’s the Analog to Digital converter! An Analog Devices AD1674 specified for 100kS/s at 12-bits. It is a ceramic DIP package – similar to early CPUs – isn’t it pretty with its golden top and purplish-grey ceramic base? It’s probably a good candidate to melt and recover the gold from (a reason why early electronics have been prized by recyclers). The date code suggests this was made in Week 27 of 1995 – 18 years ago.
The left half of the card houses many more digital discrete chips, along with the larger NEC chip – a precision programmable timer, with a 4Mhz reference oscillator. It’s amazing how simple it seems to have worked with the older ISA bus – using regular TTL chips, anything seems to have been possible!
I found another version of this card, with barely any markings but it appears to have the same pin-out and it was used in the same lab, so I figured it was an AX5411 compatible card, in this case, it was an AX5411H (I’m about 90% sure).
AX5411H differing features are: (specs from here)
- IRQ 2-15
Students of ELEC2141/ELEC2142 will probably immediately note that many of the discrete CMOS logic chips have been replaced by one Altera FPGA. And they’d be right. This is what FPGAs can do for you, folks! They made a half-size version just by changing over to an FPGA, while adding flexibility to reconfigure – and possibly offer the IRQ functionality. But, there’s sometimes a cost – in this case, the FPGA is surrounded by interfacing chips – buffers (Hitachi LS244 Non-inverting tri-state buffer) – so as to protect the FPGA and allow it to drive heavier loads (as original discrete CMOS chips have quite sizable source/sink currents compared to FPGAs).
You can see, they’ve also used the same Analog Devices AD1674 ADC, just in a surface mount package rather than a DIP ceramic package. In fact, they’ve modernized it so that everything is surface mount with finer pitches compared to DIP packages. This was probably the last hurrah before they finished up with the AX5411.
Axiom Technology is still around, although there is no support offered for these cards. As a result, I have no idea where to obtain the drivers, how to configure the jumpers, and what addresses to peek/poke to set up and get data. Oh well … another case of “lack of drivers”.
Then again, it’s likely to be high time for this card to retire. Its performance is laughable – sound cards can go faster than 60kS/s at 10-bits (192kS/s is common, as is 96kS/s at 24-bits). An Arduino is slower, at around 1-10kS/s, but it also offers TTL digital outputs and would be miles cheaper and easier to implement nowadays. The ISA bus it uses is thoroughly out of date. Of course, modern DAQ cards (say, from National Instruments) are much faster, and much higher resolving. So it’s no great loss that I can’t seem to use it …