dml attempts a Raven

[dml]

The VCCINT pins should be 5V and VCCIO pins 3.3V
(It runs 5V internally and can take 5V inputs, but drives output pins at 3.3V)

I did a very cursory check last night - really only confirmed the VCCINT correctly - but today I'll check the routing between the IC and the JTAG header, some of the other routing and will try to confirm activity on JTAG from the programmer board.

This is how it looks for me before pressing run to program it:

Thanks - everything matching here.

so maybe there's a lead to be had there, or maybe it just spits out that same message regardless of what goes wrong

According to some docs I found, seems like it might be the latter

Is it a new ATF1508 or a used one? I'm thinking in case a previous programming had some security bit checked, or maybe had jtag-isp disabled because they needed those pins for something else?

It's not a new chip, no. It's the 'spare'. The good news is I do have a new one waiting to try - but have been cautious to start with that in case there was a problem with the board. I think once I have confirmed there is no VCC on any pins that disagree with the schematic I'll change them over.

A faulty used chip is always possible but a secured/locked chip is not something I had thought about when I sourced it - you might be right about that.

BTW the very first instruction I tried was 'Blank Check', which is effectively a read. If the IC was secured, would reading the chip cause permanent damage or just not cooperate?

I did also try Program/Verify which failed. Not sure if I tried Erase at all - might be worth one more try in case it has been locked AND won't read AND isn't blank?

Edit, and this is the hardware I am using:

I have a bare-PCB version but it's the same programmer ID, same square footprint and LED is in the same place. I think it's basically the same.

[dml]

Yeah, huh.

The ATF1508AS has a 'single, security fuse'. No mention of what happens if trying to re-program with that fused. It sounds a bit permanent?

[dml]

The BSDL files I obtained from MicroChip but they were not linked properly from the site - I had to guess the correct URL to find them. It's possible these are not actually valid.

Can someone point me at a good BSD file for the ATF1508AS so I can diff it? Very unlikely to be the reason but it seems an easy thing to rule out.

[edit]

I tried a direct erase operation just now and get the same result. So I'm now looking at the connections from JTAG to IC etc.....

[agranlund]

It's not a new chip, no. It's the 'spare'. The good news is I do have a new one waiting to try - but have been cautious to start with that in case there was a problem with the board. I think once I have confirmed there is no VCC on any pins that disagree with the schematic I'll change them over.

I'll place my bets on the chip either having been secured, or that it was previously programmed to make the jtag pins GPIO which disables all JTAG-ISP functionality.

"ATF1508AS devices can also be programmed using standard third-party programmers. With third-party programmer, the JTAG ISP port can be disabled thereby allowing four additional I/O pins to be used for logic"

I think I've only ever tried Program/Verify here so I'm not sure how it should react on the other ones. I can't imagine it would cause damage attempting to read a secured chip? That sounds a bit excessive to me?

[dml]

I'll place my bets on the chip either having been secured, or that it was previously programmed to make the jtag pins GPIO which disables all JTAG-ISP functionality.

This does now seem to be the most likely explanation.

I think I've only ever tried Program/Verify here so I'm not sure how it should react on the other ones. I can't imagine it would cause damage attempting to read a secured chip? That sounds a bit excessive to me?

IIRC it is a type of protection that was implemented in some old PALs - protected against scanning by fusing something inside when the access pattern is not within some bounds decided at programming time. But I can imagine that stopped making sense at some point - it probably had extra complexity that doesn't scale. Or just plain rude.

[dml]

...and the notch on the JTAG socket is supposed to face AWAY from the mainboard, right? just checking...

[agranlund]

...and the notch on the JTAG socket is supposed to face AWAY from the mainboard, right? just checking...

Yup!

[exxos]

"ATF1508AS devices can also be programmed using standard third-party programmers

Where did you find that info? Has the algorithm been cracked? At least when I started using the ATF series you had to have the proper Atmel programmer as nothing else would program them.

[dml]

Have probed all around the 1508 and all the voltages seem to check out, up to at least pin 57.

From pin 58 onwards however (right side of the chip, with pin 1 at top) I can see a handful of IO pins are sitting at 5V instead of 3.3V everywhere else. That might be intentional but wasn't expected so I'll confirm against the schematic.

[edit]

Ok I see now those pins are pulled up to 5V in the schematic. So.... everything looks ok there.

I'll check the JTAG connections next.

[edit]

The 4 JTAG lines to the IC all appear to be good. Time to swap the chip and see what happens...

[dml]

/o/
/ \

\o\
/ \

_o_
//

\0/
/ \

This time it worked!