Having issue getting Agilent E4407B working with HXC slim.

[steve_atx]

I've finally managed to be able to read a directory that lists a file that I copied into the HFE image. I need to use a 1K resistor on R4 and R8 and HXCFESlim_V2_1_6_20a firmware. The HXCFESlim_V2_1_2_40 firmware did not work. But I'm unable to write, the instrument says that the media is write protected. I measured pin 22 and it is low. Any suggestions how to debug further? The drive being replaced is FD-05HF which works fine. Thanks!

[Jeff]

I measured pin 22 and it is low.

This is the issue : it should be high.

What is this signal level if you disconnect the floppy emulator ?

[steve_atx]

I measured that the output of pin 22 was about 30mV without the HXC. With the original floppy drive when using a non-write protected floppy I could see the voltage was around 100mV. So I put a 1K ohm from pin 22 to VDD and I can now write data. Write protect detection on the SD also works.

So the next problem I'm having is when I use the increment feature or even reinsert the SD card while the machine is on, I get "Bad, missing, or unformatted disk." The pinouts look a bit different on my drive than the one on the HXC. I did try to connect pin 9 to VSS (which goes to FLOPPY_DSKCHG# on HXC, but that had no effect. The only way is to power down and power back up the machine and then I can access the SD.

I wonder if pin 6 on the floppy needs to go to pin 9 on the HXC and pin 6 on the HXC go to pin 8 on the floppy......

FLOPPY pin/HXC pin
2 INDEX/FLOPPY_INDEX#
4 DRIVE SELECT/DS0#
6 DISK CHANGE/FLOPPY_READY# (needs 1K to VDD)
8 READY/READY_26P
9 HD OUT (HD at HIGH level)/FLOPPY_DSKCHG#
10 MOTOR ON/MTRON#
12 DIRECTION SELECT/FLOPPY_DIR#
16 WRITE DATA/FLOPPY_WDATA#
18 WRITE GATE/FLOPPY_WGATE#
20 TRACK 00/FLOPPY_TRK00#
22 WRITE PROTECT/FLOPPY_WPT# (needs 1K to VDD)
24 READ DATA/FLOPPY_DATA# (needs 1K to VDD)
26 SIDE ONE SELECT/FLOPPY_SIDE#

[Jeff]

This disk change issue is probably related to the floppy interface setting.
What was the floppy disk drive model present into this spectrum analyzer ?

[steve_atx]

The floppy drive is Teac FD-05HF. I tried many different combinations of CFG and HFE files and the only ones I could get to work are in the attached archive. I think I downloaded ones from the forum that were from one of the tektronix TDS oscilloscopes. It's strange I couldn't figure out how to make them on my own. That was one of the questions I was going to ask next. Thanks for all of the help so far, I wouldn't have gotten even this far without the forum and support.

Archive.zip

(58.47 KiB) Downloaded 45 times

[Jeff]

The floppy drive is Teac FD-05HF. I tried many different combinations of CFG and HFE files and the only ones I could get to work are in the attached archive. I think I downloaded ones from the forum that were from one of the tektronix TDS oscilloscopes. It's strange I couldn't figure out how to make them on my own. That was one of the questions I was going to ask next. Thanks for all of the help so far, I wouldn't have gotten even this far without the forum and support.
Archive.zip

I am not sure to understand : Are the Archive.zip files working properly with your Agilent E4407B ? Is there an issue ?

[steve_atx]

I can read and write a singe hfe file with that archive but the disk change and swapping SD card does not work. I need to power off and on the spectrum analyzer to access the first hfe file. Also I can’t figure out how recreate this hfe and cfg file on my own using the software. All the combinations I have tried that don’t have the auto cfg from hfe set do not work for me.

[Jeff]

I wonder if pin 6 on the floppy needs to go to pin 9 on the HXC and pin 6 on the HXC go to pin 8 on the floppy......

FLOPPY pin/HXC pin
2 INDEX/FLOPPY_INDEX#
4 DRIVE SELECT/DS0#
6 DISK CHANGE/FLOPPY_READY# (needs 1K to VDD)
8 READY/READY_26P
9 HD OUT (HD at HIGH level)/FLOPPY_DSKCHG#
10 MOTOR ON/MTRON#
12 DIRECTION SELECT/FLOPPY_DIR#
16 WRITE DATA/FLOPPY_WDATA#
18 WRITE GATE/FLOPPY_WGATE#
20 TRACK 00/FLOPPY_TRK00#
22 WRITE PROTECT/FLOPPY_WPT# (needs 1K to VDD)
24 READ DATA/FLOPPY_DATA# (needs 1K to VDD)
26 SIDE ONE SELECT/FLOPPY_SIDE#

the pin 6 "DISK CHANGE" match with the pin 34 ibm pc pin.

this is connected this way in the slim hxc :

https://hxc2001.com/download/floppy_dri ... Design.zip

Screenshot at 2025-05-09 11-56-30.png (125.26 KiB) Viewed 1442 times

You should have this behavior on this pin :

https://bitsavers.org/pdf/teac/FD-05HF-8830.pdf

Screenshot at 2025-05-09 11-53-30.png (33.33 KiB) Viewed 1443 times

Note : When the drive selection is high the diskchange signal should be high too !
Note 2 : Low = something near 0v, High = Something around 5V.

Is it the case with your setup ?

[steve_atx]

Finally got around to checking this pin 6 "DISK CHANGE" ( 34 ibm pc pin) the yellow trace. The "STEP" is the magenta trace. When I insert or change the disk there isn't any change on DISC CHANGE (stays high) unless I push a button on the machine to read the disk. Then 4 to 6 low going pulses appear on "DISK CHANGE" depending on the resistor pull-up value. They won't appear unless a pull-up resistor is used. The last pulse will eventually stay at ground if a large enough resistor pull-up is used. Guessing that if the last in the series of three low going pulses can't return to a high enough voltage the drive will driving "DISK CHANGE" low on the last pulse. I'm not sure what's going on but with 470K the disk change feature now works for me. Finally with the 470K pull-up in place after enough time when the "STEP" pulse goes low the "DISK CHANGE" is released and pulls back up to VDD. With 220K it seems to pull-high through another mechanism.

Another issue I had was to get write-protect to sense both states I needed a 100K pull-up.

Here are the list of resistors now. Pretty sure I need all of these....

6 DISK CHANGE/FLOPPY_READY# (needs 470K - R4 to VDD)
9 HD OUT (HD at HIGH level)/FLOPPY_DSKCHG# (needs 1K - R9 to VDD)
22 WRITE PROTECT/FLOPPY_WPT# (needs 100K to VDD)
24 READ DATA/FLOPPY_DATA# (needs 1K - R8 to VDD)

[steve_atx]

The longer time waveforms:

[Jeff]

6 DISK CHANGE/FLOPPY_READY# (needs 470K - R4 to VDD)
9 HD OUT (HD at HIGH level)/FLOPPY_DSKCHG# (needs 1K - R9 to VDD)
22 WRITE PROTECT/FLOPPY_WPT# (needs 100K to VDD)
24 READ DATA/FLOPPY_DATA# (needs 1K - R8 to VDD)

470K,100K, 220K : i suppose you mean "R/ohms" instead of "K" ?

I understand that you fixed the issue, isn't it ?

[steve_atx]

Everything is working properly now, write protect and disk change. K is for kiloohm. So 470K is 470000 ohm. I’m not sure why my waveforms for disk change are so different than the teac spec waveform you sent and I have only a theory why the disk change is working now with the 470K pull-up. If you have any idea let me know.