Issue writing data on floppy (Write protected)

[geogeo_28]

I known this issue has already been addressed by Exxos and the pull-up fix on the data lines of the WD1772 but in my case this does not solve the problem.

My ATARI STe does not have issue reading disks but when I want to write data, I always end up with Write Protected Error. This happens when I start a copy, create a folder or at the end of a format. The most surprising is, even if I obtain this error, the TOS succeeds to format or create a folder.

I replaced the WD1772 without success, same issue. I checked the signal WP and no problem here.
I have the floppy mod from Exxos. When I use this mod, instead of having the write protected error, I end-up with `Data on the disk may be Damaged`.

My ATARI STe has a booster 8/32 MHz. Surprisingly when I switch to 32 MHz, I can sometimes format, write data, without issue.
This let me suspect that some noise make the signal WP appears on the bus.

I have the infamous DMA C025913-38, I probe the data lines no issue really.
But when I probe the RDY signal, by magic, no more write issue. I can format and copy data.

I suspect the small spike at the end to be the root cause of the issue.
What will be the best way to filter this signal?

IMG_0539.jpeg

[exxos]

Odd.. Right at the start I think my first mod was to rdy if you check my DMA page on my website.. But the pull ups on the DMA bus solved it.. My 1.44 board has the pull ups , but also don't forget there's another lot of pull ups on the inverter connected to the 1772 in mandatory fixes..

[geogeo_28]

I am using a Gotek which has already some pull-ups on shugart bus + your 1.44 board (setup at double density for now) with the pull-ups on the DMA side?
I tried to replace the R303 from 1K to 1.5K without success.
One mod missing is the bus resistors on the CPU side but not sure if this is necessary with the STE Booster?

[exxos]

The ste booster has bus pull ups on it already..

This is what I found but its done already https://www.exxosforum.co.uk/forum/viewt ... =23&t=1410

You should try a proper floppy drive to see if that works...

[geogeo_28]

I am kind of puzzle, because the Gotek works without issue on the Atari STF.
Same problem of write protected with the original floppy drive of the Atari STE and the High Density one.
I can read without issue, but cannot write.

In your thread you had the same issue than me and add an extra pull-up on RDY? I see also a small spike at the end. I am wondering if this is normal or not?

[exxos]

Have you checked the 1772 data bus is connected to the DMA pins ? The RDY work was really old work, it was found that bit problems on the DMA/1772 bus was the cause.. possible broken trace somewhere ?

[geogeo_28]

I checked all the pins between 1772 and the DMA and everything look fine.
All data and address lines are fine.

[exxos]

Well only thing is to try the original fix.. I think it was 390pf to gnd on rdy.

[geogeo_28]

Ok let me try this fix. ;)

[geogeo_28]

Nop same issue with a capacitor of 400 pF on RDY and GND.

Here is what I have:

IMG_0563.jpeg

Here is what I get after formatting with the floppy board:

IMG_0566.jpeg

When doing nothing, I see the following noise, spike on RDY signal:

IMG_0569.jpeg

I probe each pin of 1772:
WD

IMG_0543.jpeg

DRQ

IMG_0544.jpeg

INTRQ

IMG_0545.jpeg

IP

IMG_0546.jpeg

WG

IMG_0547.jpeg

MO

IMG_0548.jpeg

CS

IMG_0549.jpeg

R/W

IMG_0550.jpeg

A0

IMG_0551.jpeg

A1

IMG_0552.jpeg

D0

IMG_0553.jpeg

D1

IMG_0554.jpeg

D2

IMG_0555.jpeg

D3, D4, D5, D6, D7 same

CLK

IMG_0561.jpeg

RDY

IMG_0565.jpeg

The signal RDY looks weird from my point of view. Seeing this spike at 2.3V when doing nothing.
DRQ, INTRQ, WG, MO seem a little too weak below 5V.