[N8VEM: 19648] N8-4314 Issues

[RichLeary]

I have decided to put the N8-4314 on the back burner for a while. Issues
that force this are:

a. As I have otherwise noted there is at least one schematic change that I
know about. That is the addition of a K1 three-pin header near RR6. However
there is no schematic for this board and the only way I noted this was a
change is by comparing the bare board to the N8-2312 layout. There may be
other changes but given the lack of a schematic those changes can only be
discovered by accident. Even in the case of the one I discovered there is
no information describing the why and wherefore of the new header.

b. There are routing changes. I discovered one while trying to track down
the cause of an issue. As was the case with the schematic there is no way
to understand them as there is no layout information.

c. The solder mask layer (red for the N8-4314) does not behave as well as
the green solder mask usually used with N8VEM boards. In particular any
solder splashes with the red mask tend to stick to the mask and removal
damages the integrity of the mask. That is not the case with my experience
with other N8VEM-associated ECB and S100 boards. In those cases any splash
does not stick to the mask and a quick poke with a toothpick will separate
the splash from the mask with no harm to the mask.

d. I have encountered at least one open trace. In the case referenced above
I was trying to determine why I was getting no SD LED response when reading
or writing to the SD card. The trace from U11-17 to U8-1 is open. I have
not found where the open is located so I will probably fix it with a wire
jumper between those two pins. That raises concern about possible other
open or fragile traces.

e. The board as currently populated has a thermal issue. I will not start
up when cold

I appeal again to the community. Someone must have schematics and layouts
fro the 4314 board. Please put them on PBWorks.

If anyone has a bare N8-2312 board they are willing to sell please let my
know.

Thanks,

Rich Leary

[Fabio Battaglia]

Hello Rich,
As far as I remember, that run of boards was made by Todd Goodman. Maybe
you can ask him who provided the gerbers for production and see if there
are the schematics available too.

Hopefully the 4314 was not made while a change/fix was still
work-in-progress...

Fabio
I have decided to put the N8-4314 on the back burner for a while. Issues
that force this are:

a. As I have otherwise noted there is at least one schematic change that I
know about. That is the addition of a K1 three-pin header near RR6. However
there is no schematic for this board and the only way I noted this was a
change is by comparing the bare board to the N8-2312 layout. There may be
other changes but given the lack of a schematic those changes can only be
discovered by accident. Even in the case of the one I discovered there is
no information describing the why and wherefore of the new header.

b. There are routing changes. I discovered one while trying to track down
the cause of an issue. As was the case with the schematic there is no way
to understand them as there is no layout information.

c. The solder mask layer (red for the N8-4314) does not behave as well as
the green solder mask usually used with N8VEM boards. In particular any
solder splashes with the red mask tend to stick to the mask and removal
damages the integrity of the mask. That is not the case with my experience
with other N8VEM-associated ECB and S100 boards. In those cases any splash
does not stick to the mask and a quick poke with a toothpick will separate
the splash from the mask with no harm to the mask.

d. I have encountered at least one open trace. In the case referenced above
I was trying to determine why I was getting no SD LED response when reading
or writing to the SD card. The trace from U11-17 to U8-1 is open. I have
not found where the open is located so I will probably fix it with a wire
jumper between those two pins. That raises concern about possible other
open or fragile traces.

e. The board as currently populated has a thermal issue. I will not start
up when cold

I appeal again to the community. Someone must have schematics and layouts
fro the 4314 board. Please put them on PBWorks.

If anyone has a bare N8-2312 board they are willing to sell please let my
know.

Thanks,

Rich Leary
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[Todd Goodman]

Hi Rich,

Those boards were produced from the EDA files in ECB HC3-003.zip on
N8VEM. (http://n8vem-sbc.pbworks.com/w/browse/#view=ViewFolder&param=ECB%20N8%20previously%20known%20as%20the%20Home%20Computer)

You can generate schematics with KiCad with those files. I've
attached the generated schematics.

I don't remember who was designing the board but I think it was Andrew.

I'm surprised about the soldermask as I've made up boards with every
color soldermask that PCBCart offers and haven't heard of anyone else
having trouble with them. But I'll certainly keep that in mind for
the future.

Thanks,

Todd

Post by Fabio Battaglia
Hello Rich,
As far as I remember, that run of boards was made by Todd Goodman. Maybe you
can ask him who provided the gerbers for production and see if there are the
schematics available too.
Hopefully the 4314 was not made while a change/fix was still
work-in-progress...
Fabio
I have decided to put the N8-4314 on the back burner for a while. Issues
a. As I have otherwise noted there is at least one schematic change that I
know about. That is the addition of a K1 three-pin header near RR6. However
there is no schematic for this board and the only way I noted this was a
change is by comparing the bare board to the N8-2312 layout. There may be
other changes but given the lack of a schematic those changes can only be
discovered by accident. Even in the case of the one I discovered there is no
information describing the why and wherefore of the new header.
b. There are routing changes. I discovered one while trying to track down
the cause of an issue. As was the case with the schematic there is no way to
understand them as there is no layout information.
c. The solder mask layer (red for the N8-4314) does not behave as well as
the green solder mask usually used with N8VEM boards. In particular any
solder splashes with the red mask tend to stick to the mask and removal
damages the integrity of the mask. That is not the case with my experience
with other N8VEM-associated ECB and S100 boards. In those cases any splash
does not stick to the mask and a quick poke with a toothpick will separate
the splash from the mask with no harm to the mask.
d. I have encountered at least one open trace. In the case referenced above
I was trying to determine why I was getting no SD LED response when reading
or writing to the SD card. The trace from U11-17 to U8-1 is open. I have not
found where the open is located so I will probably fix it with a wire jumper
between those two pins. That raises concern about possible other open or
fragile traces.
e. The board as currently populated has a thermal issue. I will not start up
when cold
I appeal again to the community. Someone must have schematics and layouts
fro the 4314 board. Please put them on PBWorks.
If anyone has a bare N8-2312 board they are willing to sell please let my
know.
Thanks,
Rich Leary
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[John Coffman]

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After some tracking of dates on schematics:<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp; proto&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; schematic dated 26-Mar-2011 -- this may be an
intermediate between the actual prototype and the 2511 issue<br>
&nbsp;&nbsp;&nbsp; N8-2511&nbsp;&nbsp;&nbsp; schematic dated 29-Jun-2011<br>
&nbsp;&nbsp;&nbsp; N8-2312&nbsp;&nbsp;&nbsp; schematic dated 17-Dec-2011 -- touted as "final"<br>
&nbsp;&nbsp;&nbsp; N8-4314&nbsp;&nbsp;&nbsp; schematic dated 26-Jan-2013&nbsp; -- <br>
<br>
Rich's clue that the 3-pin jumper was near RR6, which is near pins
C-26 &amp; C-31, indicated to me that it was probably the
N8VEM/Kontron reset jumper.&nbsp; It is.<br>
<br>
All of the schematics bear the name "HC3," which is especially
confusing.<br>
<br>
Andrew was the source for the boards up through 2312.&nbsp; The present
Kicad files on the Wiki are for the 4314 board.&nbsp; This looks like a
2312 + Kontron jumper.<br>
<br>
--John<br>
<br>
<br>
<br>
<br>
<br>
<br>
On 05/25/2015 06:26 AM, Todd Goodman wrote:
<blockquote
cite="mid:CADbUL+K+rpSbQmbtcOnxC3mTf0CB-wZr_VGkpwiLZBd+***@mail.gmail.com"
type="cite">
<pre wrap="">Hi Rich,

Those boards were produced from the EDA files in ECB HC3-003.zip on
N8VEM. (<a class="moz-txt-link-freetext" href="http://n8vem-sbc.pbworks.com/w/browse/#view=ViewFolder&amp;param=ECB%20N8%20previously%20known%20as%20the%20Home%20Computer">http://n8vem-sbc.pbworks.com/w/browse/#view=ViewFolder&amp;param=ECB%20N8%20previously%20known%20as%20the%20Home%20Computer</a>)

You can generate schematics with KiCad with those files. I've
attached the generated schematics.

I don't remember who was designing the board but I think it was Andrew.

I'm surprised about the soldermask as I've made up boards with every
color soldermask that PCBCart offers and haven't heard of anyone else
having trouble with them. But I'll certainly keep that in mind for
the future.

Thanks,

Todd



On Mon, May 25, 2015 at 1:16 AM, Fabio Battaglia <a class="moz-txt-link-rfc2396E" href="mailto:***@gmail.com">&lt;***@gmail.com&gt;</a> wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Hello Rich,
As far as I remember, that run of boards was made by Todd Goodman. Maybe you
can ask him who provided the gerbers for production and see if there are the
schematics available too.

Hopefully the 4314 was not made while a change/fix was still
work-in-progress...

Fabio

I have decided to put the N8-4314 on the back burner for a while. Issues
that force this are:

a. As I have otherwise noted there is at least one schematic change that I
know about. That is the addition of a K1 three-pin header near RR6. However
there is no schematic for this board and the only way I noted this was a
change is by comparing the bare board to the N8-2312 layout. There may be
other changes but given the lack of a schematic those changes can only be
discovered by accident. Even in the case of the one I discovered there is no
information describing the why and wherefore of the new header.

b. There are routing changes. I discovered one while trying to track down
the cause of an issue. As was the case with the schematic there is no way to
understand them as there is no layout information.

c. The solder mask layer (red for the N8-4314) does not behave as well as
the green solder mask usually used with N8VEM boards. In particular any
solder splashes with the red mask tend to stick to the mask and removal
damages the integrity of the mask. That is not the case with my experience
with other N8VEM-associated ECB and S100 boards. In those cases any splash
does not stick to the mask and a quick poke with a toothpick will separate
the splash from the mask with no harm to the mask.

d. I have encountered at least one open trace. In the case referenced above
I was trying to determine why I was getting no SD LED response when reading
or writing to the SD card. The trace from U11-17 to U8-1 is open. I have not
found where the open is located so I will probably fix it with a wire jumper
between those two pins. That raises concern about possible other open or
fragile traces.

e. The board as currently populated has a thermal issue. I will not start up
when cold

I appeal again to the community. Someone must have schematics and layouts
fro the 4314 board. Please put them on PBWorks.

If anyone has a bare N8-2312 board they are willing to sell please let my
know.

Thanks,

Rich Leary

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</pre>
</blockquote>
<pre wrap="">
</pre>
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['Bob Grieb' via N8VEM]

Hello,
    I have an N8 board that I built up and had working.  As other projects have come up,I doubt I will have time to do any more with this, so if someone would like to buy it,please contact me.   I am only interested in selling the whole board with the parts installed,not individual chips or just the board.    It is populated with mostly 74HC chips, and has
eight jumper wires on the bottom.   I think everything that I tested was working, but I didn't try
the SD card or some of the other features. 

    The CPU is ZS18033VSG.   It has a TMS9918A and also an AY-3-8910A.   I seem to
recall playing with some code to test both of those chips.  The CPU can osc is 6.144 MHz
     I can supply a photo of the board.
     I looked for some sort of identifying number but found none.   I am thinking that this
may have been the first "N8" board, and not the "home computer".   If anyone is interestedI am sure it will be easy to figure out which one it is.
     Thanks,
           Bob Grieb

From: RichLeary <***@gmail.com>
To: ***@googlegroups.com
Sent: Monday, May 25, 2015 1:06 AM
Subject: [N8VEM: 19648] N8-4314 Issues

I have decided to put the N8-4314 on the back burner for a while. Issues that force this are:
a. As I have otherwise noted there is at least one schematic change that I know about. That is the addition of a K1 three-pin header near RR6. However there is no schematic for this board and the only way I noted this was a change is by comparing the bare board to the N8-2312 layout. There may be other changes but given the lack of a schematic those changes can only be discovered by accident. Even in the case of the one I discovered there is no information describing the why and wherefore of the new header.
b. There are routing changes. I discovered one while trying to track down the cause of an issue. As was the case with the schematic there is no way to understand them as there is no layout information.
c. The solder mask layer (red for the N8-4314) does not behave as well as the green solder mask usually used with N8VEM boards. In particular any solder splashes with the red mask tend to stick to the mask and removal damages the integrity of the mask. That is not the case with my experience with other N8VEM-associated ECB and S100 boards. In those cases any splash does not stick to the mask and a quick poke with a toothpick will separate the splash from the mask with no harm to the mask.
d. I have encountered at least one open trace. In the case referenced above I was trying to determine why I was getting no SD LED response when reading or writing to the SD card. The trace from U11-17 to U8-1 is open. I have not found where the open is located so I will probably fix it with a wire jumper between those two pins. That raises concern about possible other open or  fragile traces.
e. The board as currently populated has a thermal issue. I will not start up when cold
I appeal again to the community. Someone must have schematics and layouts fro the 4314 board. Please put them on PBWorks.
If anyone has a bare N8-2312 board they are willing to sell please let my know.  
Thanks,
Rich Leary--
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[RichLeary]

Bob - thanks but I will pass for now. I will work with what I have for now.

Rich Leary

[RichLeary]

In spite of saying I was putting my N8-4314 on the back burner I have been
doing some testing and trouble shooting.

Configuration: Latest CPU, 18.432 MHz CPU Osc, 512KB 70 nsec flash with
ROMWBW 2.7.1, 2 x 512KB RAM, ECB buffers not installed but U43 is, all
40-pin ICs installed, 8255's are the Toshiba 10 MHz part, FDC and
associated HW installed, SD populated and installed, video 32KB RAM not
installed, only 74ALS574 installed is U11.

Status:

a. Board boots from ROM and will boot either to CPM or ZSYSTEM.
b. ROMWBW does not recognize 2nd 512KB R FSM but that was expected given
ROM configuration.
c. Serial port working well at 38.4 kbps with HW handshaking.
d. XM-A0 working.
e. SD card and interface working well..

Issues:
e. K1, K20 jumpering still not clear
b. RTC not working - I have checked runs and all appears OK. Quick checks
with logic probe show correct static levels and activity when there should
be activity.

Other functions not tested yet.

RTC is the road block now. Any hints would be appreciated.

Rich Leary

[Wayne Warthen]

Hi Rich,

How are you testing RTC? What does RomWBW show during boot?

Have you tried the RTC.COM app that should be on the ROM?

Thanks,

Wayne

Post by RichLeary
In spite of saying I was putting my N8-4314 on the back burner I have been
doing some testing and trouble shooting.
Configuration: Latest CPU, 18.432 MHz CPU Osc, 512KB 70 nsec flash with
ROMWBW 2.7.1, 2 x 512KB RAM, ECB buffers not installed but U43 is, all
40-pin ICs installed, 8255's are the Toshiba 10 MHz part, FDC and
associated HW installed, SD populated and installed, video 32KB RAM not
installed, only 74ALS574 installed is U11.
a. Board boots from ROM and will boot either to CPM or ZSYSTEM.
b. ROMWBW does not recognize 2nd 512KB R FSM but that was expected given
ROM configuration.
c. Serial port working well at 38.4 kbps with HW handshaking.
d. XM-A0 working.
e. SD card and interface working well..
e. K1, K20 jumpering still not clear
b. RTC not working - I have checked runs and all appears OK. Quick checks
with logic probe show correct static levels and activity when there should
be activity.
Other functions not tested yet.
RTC is the road block now. Any hints would be appreciated.
Rich Leary

[Richard Leary]

I have been trying to use the RTC.COM included and it shows junk but consistent junk. T yields
??-3?-3? 3?:7?:7?-??
No amount of starting, initing, set changes anything. Put changes nothing.

ROMWBW shows
INIT CLOCK Tue 20FF-FF-FF FF:FF:FF

Richard A. Leary (Rich)
180 Ridge Rd
Cimarron, CO 81220

***@gmail.com
HOME: [phone]
FAX: [phone]
iPhone: [phone]

Post by Todd Goodman
Hi Rich,
How are you testing RTC? What does RomWBW show during boot?
Have you tried the RTC.COM app that should be on the ROM?
Thanks,
Wayne

In spite of saying I was putting my N8-4314 on the back burner I have been doing some testing and trouble shooting.
Configuration: Latest CPU, 18.432 MHz CPU Osc, 512KB 70 nsec flash with ROMWBW 2.7.1, 2 x 512KB RAM, ECB buffers not installed but U43 is, all 40-pin ICs installed, 8255's are the Toshiba 10 MHz part, FDC and associated HW installed, SD populated and installed, video 32KB RAM not installed, only 74ALS574 installed is U11.
a. Board boots from ROM and will boot either to CPM or ZSYSTEM.
b. ROMWBW does not recognize 2nd 512KB R FSM but that was expected given ROM configuration.
c. Serial port working well at 38.4 kbps with HW handshaking.
d. XM-A0 working.
e. SD card and interface working well..
e. K1, K20 jumpering still not clear
b. RTC not working - I have checked runs and all appears OK. Quick checks with logic probe show correct static levels and activity when there should be activity.
Other functions not tested yet.
RTC is the road block now. Any hints would be appreciated.
Rich Leary

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[RichLeary]

One other strange situation but perhaps is as intended. The SD LED is
always on. I thought it was an "activity" light but if so there is
something wrong there also.

I may try creating some ad-hoc test routines that write to the register
(U11) that controls the RTC and the SD CS that turns the SD LED ON-OFF.

BTW - I tried RTC with my Mark 4 and while the UNA BIOS reported the
correct date and time on start up, RTC did not work. Does RTC not work with
faster processors?

Rich Leary

[RichLeary]

I may be jumping to a very bad conclusion but I dug through the ROMWBW
2.7.1 source code. It looks to me like it puts the RTC register (U11 for
the N8) at $70. But if the N8 base IO address is set to $80 as
recommended then the RTC port is at $88. There is no way to separately
specify the RTC register address.

I suspect that RTC.COM also assumes that the register is at $70 and that
explains why RTC.COM is not working for N8 and Mk4 but works with my V1. I
have not found the source code for RTC.COM but I will continue to look for
it.

I also need to find where the ROMWBW 2.7.1 SD driver is told where it's CS
bit is located. If it assumes the register is at $70 that would explain why
Q02 never changes state.

Rich Leary

[John Coffman]

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On 05/29/2015 10:32 PM, RichLeary wrote:
<blockquote
cite="mid:c1599ebb-3a82-4248-be40-***@googlegroups.com"
type="cite">
<div dir="ltr">
<div>I may be jumping to a very bad conclusion but I dug through
the ROMWBW 2.7.1 source code. It looks to me like it puts the
RTC register (U11 for the N8) at $70. But if the N8 base IO
address is set to $80 as recommended&nbsp;then the RTC port is
at&nbsp;$88. There is no way to separately specify the RTC register
address.</div>
<div><br>
</div>
<div>I suspect that RTC.COM also assumes that the register is at
$70 and that explains why RTC.COM is not working for N8 and
Mk4 but works with my V1. I have not found the source code for
RTC.COM but I will continue to look for it.</div>
</div>
</blockquote>
<br>
RTC.COM was probably written for the SBC v1.&nbsp; So the device code is
uses is only valid on SBC v1, SBC v2, &amp; Zeta.&nbsp; It definitely is
the wrong device code for the N8 &amp; Mark IV.<br>
<br>
--John<br>
<br>
<br>
<br>
<blockquote
cite="mid:c1599ebb-3a82-4248-be40-***@googlegroups.com"
type="cite">
<div dir="ltr">
<div><br>
</div>
<div>I also need to find where the ROMWBW 2.7.1&nbsp;SD driver is
told where it's CS bit is located. If it assumes the register
is at $70 that would explain why Q02 never changes state.</div>
<div><br>
</div>
<div>Rich Leary</div>
<div><br>
</div>
</div>
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[Wayne Warthen]

Both RomWbw AND the RTC code was modified for the N8 and both were working a while back. Maybe I broke it in a recent release. I will check both on my N8-2312 tonight.

Wayne

[RichLeary]

Wayne - thanks! Maybe I have a really dumb error on my part but I sure am
not seeing it.

Rich Leary

Post by Wayne Warthen
Both RomWbw AND the RTC code was modified for the N8 and both were working
a while back. Maybe I broke it in a recent release. I will check both on
my N8-2312 tonight.
Wayne

[Wayne Warthen]

Hi Rich,

OK, I downloaded the exact RomWBW v2.7.1 image from the Wiki and burned
that image to my N8-2312. The RTC seems to be working fine. It is
recognized and displays the correct date/time at RomWBW boot. Using the
RTC application, I type T and the correct time is displayed.

I have not checked the schematics, but agree that the RomWBW code expects
the RTC latch to be at $88. Additionally, the RTC.COM app in the N8 ROM
disk has been customized to expect the latch to also be at $88. The source
for RTC.COM is not part of the RomWBW distribution, but I am attaching a
zip file here with my custom build -- it allows the app to be built for
several different N8VEM hardware variants.

Regarding the CS bit for the SD driver... that is defined in sd.asm. Note
that the N8-2312 uses the CSIO mode, not the N8 mode. The N8 mode is only
for the older N8-2511. As defined in sd.asm, the CS bit is bit 2 of of the
RTC latch register at $88.

I am very puzzled by the fact that your SD card is working, but neither the
RTC nor your SD LED are working. I guess the SD LED failure could simply
be an open somewhere. However, I don't see how the SD card could be
working unless the RTC latch is being addressed properly. The RTC latch
controls the CS signal to the SD card, so it seems like the latch
addressing at $88 is OK.

The output of RomWBW and RTC.COM you shared makes it look like the DS-1302
is either dead or not getting the proper signals. You should be able to
confirm all of the signals at the DS-1302 with your logic probe and use a
debugger to manually flip the signals at the RTC latch. Don't suppose you
have another DS-1302 you could try?

Hope this is helpful. Please post your progress.

Thanks,

Wayne

Post by RichLeary
Wayne - thanks! Maybe I have a really dumb error on my part but I sure am
not seeing it.
Rich Leary

Post by Wayne Warthen
Both RomWbw AND the RTC code was modified for the N8 and both were
working a while back. Maybe I broke it in a recent release. I will check
both on my N8-2312 tonight.
Wayne

[Wayne Warthen]

Rich,

Have you confirmed +5V at pin 8 of the DS-1302? How do you have P45
configured? SuperCap? If no SuperCap, pins 1-2 need to be shorted.

--Wayne

Post by Todd Goodman
Hi Rich,
OK, I downloaded the exact RomWBW v2.7.1 image from the Wiki and burned
that image to my N8-2312. The RTC seems to be working fine. It is
recognized and displays the correct date/time at RomWBW boot. Using the
RTC application, I type T and the correct time is displayed.
I have not checked the schematics, but agree that the RomWBW code expects
the RTC latch to be at $88. Additionally, the RTC.COM app in the N8 ROM
disk has been customized to expect the latch to also be at $88. The source
for RTC.COM is not part of the RomWBW distribution, but I am attaching a
zip file here with my custom build -- it allows the app to be built for
several different N8VEM hardware variants.
Regarding the CS bit for the SD driver... that is defined in sd.asm. Note
that the N8-2312 uses the CSIO mode, not the N8 mode. The N8 mode is only
for the older N8-2511. As defined in sd.asm, the CS bit is bit 2 of of the
RTC latch register at $88.
I am very puzzled by the fact that your SD card is working, but neither
the RTC nor your SD LED are working. I guess the SD LED failure could
simply be an open somewhere. However, I don't see how the SD card could be
working unless the RTC latch is being addressed properly. The RTC latch
controls the CS signal to the SD card, so it seems like the latch
addressing at $88 is OK.
The output of RomWBW and RTC.COM you shared makes it look like the
DS-1302 is either dead or not getting the proper signals. You should be
able to confirm all of the signals at the DS-1302 with your logic probe and
use a debugger to manually flip the signals at the RTC latch. Don't
suppose you have another DS-1302 you could try?
Hope this is helpful. Please post your progress.
Thanks,
Wayne

Post by RichLeary
Wayne - thanks! Maybe I have a really dumb error on my part but I sure am
not seeing it.
Rich Leary

Post by Wayne Warthen
Both RomWbw AND the RTC code was modified for the N8 and both were
working a while back. Maybe I broke it in a recent release. I will check
both on my N8-2312 tonight.
Wayne

[Richard Leary]

Wayne,



As they say – great minds think alike. I had a SuperCap in P45 but was only seeing 100 mv or so on pin 8 of the 1302. So last night I removed it after trying two different 1302’s.



I thought I had an unused SuperCap but could not find it so I have an order coming from DigiKey with a handful of SuperCaps and a handful of 1302’s in case I destroyed the two unused ones I have due to a bad SuperCap.



I also found the rtc.asm and built a version at 88h but was seeing the same issue before I de-soldered the SuperCap.



I have not tried a P45 jumper 1-2 but will do that tomorrow while I wait for my shipment.



Thanks for your help.



One unanswered question is if the SD LED should be on all the time (mine is) or if it should only light when an actual SD access is in process.



Otherwise the SD interface is working quite well even with the SD CS always asserted as indicated by the always on SD LED.



I will report progress.



Rich Leary

[John Coffman]

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Rich,<br>
<br>
If SD-CS is always asserted, you will not be able to access the
SD-card.&nbsp; By SD-CS, I mean the 3.3v/0v signal on the card /CS on
pin1 -- watch out for weird pin numbering on the socket.&nbsp; Normal
state should be de-asserted at +3.3v.&nbsp; 0v to access the card.<br>
<br>
The /CS on/off state is used by the card to synchronize to the
serial bit stream, so it must be toggling.<br>
<br>
--John<br>
<br>
<br>
<br>
On 05/30/2015 10:20 PM, Richard Leary wrote:
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<p class="MsoNormal"><span style="font-size: 11pt; font-family:
&quot;Calibri&quot;,sans-serif; color: rgb(31, 73, 125);">Wayne,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
&quot;Calibri&quot;,sans-serif; color: rgb(31, 73, 125);"><o:p>&nbsp;</o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
&quot;Calibri&quot;,sans-serif; color: rgb(31, 73, 125);">As
they say &acirc;&#8364;&#8220; great minds think alike. I had a SuperCap in
P45 but was only seeing 100 mv or so on pin 8 of the 1302.
So last night I removed it after trying two different
1302&acirc;&#8364;&#8482;s.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
&quot;Calibri&quot;,sans-serif; color: rgb(31, 73, 125);"><o:p>&nbsp;</o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
&quot;Calibri&quot;,sans-serif; color: rgb(31, 73, 125);">I
thought I had an unused SuperCap but could not find it so I
have an order coming from DigiKey with a handful of
SuperCaps and a handful of 1302&acirc;&#8364;&#8482;s in case I destroyed the
two unused ones I have due to a bad SuperCap.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
&quot;Calibri&quot;,sans-serif; color: rgb(31, 73, 125);"><o:p>&nbsp;</o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
&quot;Calibri&quot;,sans-serif; color: rgb(31, 73, 125);">I
also found the rtc.asm and built a version at 88h but was
seeing the same issue before I de-soldered the SuperCap.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
&quot;Calibri&quot;,sans-serif; color: rgb(31, 73, 125);"><o:p>&nbsp;</o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
&quot;Calibri&quot;,sans-serif; color: rgb(31, 73, 125);">I
have not tried a P45 jumper 1-2 but will do that tomorrow
while I wait for my shipment.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
&quot;Calibri&quot;,sans-serif; color: rgb(31, 73, 125);"><o:p>&nbsp;</o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
&quot;Calibri&quot;,sans-serif; color: rgb(31, 73, 125);">Thanks
for your help. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
&quot;Calibri&quot;,sans-serif; color: rgb(31, 73, 125);"><o:p>&nbsp;</o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
&quot;Calibri&quot;,sans-serif; color: rgb(31, 73, 125);">One
unanswered question is if the SD LED should be on all the
time (mine is) or if it should only light when an actual SD
access is in process.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
&quot;Calibri&quot;,sans-serif; color: rgb(31, 73, 125);"><o:p>&nbsp;</o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
&quot;Calibri&quot;,sans-serif; color: rgb(31, 73, 125);">Otherwise
the SD interface is working quite well even with the SD CS
always asserted as indicated by the always on SD LED.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
&quot;Calibri&quot;,sans-serif; color: rgb(31, 73, 125);"><o:p>&nbsp;</o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
&quot;Calibri&quot;,sans-serif; color: rgb(31, 73, 125);">I
will report progress.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
&quot;Calibri&quot;,sans-serif; color: rgb(31, 73, 125);"><o:p>&nbsp;</o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family:
&quot;Calibri&quot;,sans-serif; color: rgb(31, 73, 125);">Rich
Leary<o:p></o:p></span></p>
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[RichLeary]

I think I have determined the cause of my problems. Recall that I
complained of solder sticking to the solder mask much harder than I had
ever seen. It turns out that my efforts to remove the solder caused some
breaks in traces. I had previously fixed one for which I could not even see
a break. One of the ones I discovered today was a break in one or more of
the data lines going to U11. That explains why the RTC was not working.

I have pulled all ICs and will try to determine where the breaks are and
then fix them. If that fails I have a second bare board and may go ahead
and build that up.

Either way this will take a good while to do so stand by for try number 2.

In the meantime thanks for the help. John Coffman probably pointed my in
the right direction when he suggested that the required signals were not
getting to the 1302 and from there it was a case of using probe and scope
to confirm suspicion. This is a first time situation for me after decades
of electronic work hence my slowness in identifying the root cause. Won't
happen again.

Rich Leary

[RichLeary]

Great News - my second attempt at building a N8-4314 appears to be a good
one. System booted right up using ROMWBW 2.7.1 and is totally stable. SD
card and LED are working as expected. RTC is working correctly.

I need to test floppy interface and just for fun exercise some of the other
I/O including the video, PS2 keyboard, and audio. I need to do some
research on that score. As is, the 9918 appears to be responding to some
ROMWBW initialization as the screen shows a full screen of the same symbol
after a reset. The usual lights on a connected keyboard are dark - do not
know if that means anything.

A note on as-built configuration. I used all 74LS logic except for the
574's that are 74ALS574's just because I did not immediately find 74LS574's
at DigiKey, my preferred source. CPU oscillator is 18.432 MHz. Since I have
no plans to use the ECB interface I have not set the K1 configuration -
there is no jumper on K1. K21 & K22 are set to 1-2 jumpered but the two
4700 ohm resistors are still in place - without anything connected to the
ECB bus this should also be a "don't care".

Rich Leary

[Wayne Warthen]

Hi Rich,

A few comments below...

--Wayne

Post by RichLeary
Great News - my second attempt at building a N8-4314 appears to be a good
one. System booted right up using ROMWBW 2.7.1 and is totally stable. SD
card and LED are working as expected. RTC is working correctly.

Glad it the RTC is working on this one.

Post by RichLeary
I need to test floppy interface and just for fun exercise some of the
other I/O including the video, PS2 keyboard, and audio. I need to do some
research on that score. As is, the 9918 appears to be responding to some
ROMWBW initialization as the screen shows a full screen of the same symbol
after a reset. The usual lights on a connected keyboard are dark - do not
know if that means anything.

RomWBW initializes the screen to blanks. If you see a screen full of some
character, that does imply the video chip is working, but also implies that
the system is running too fast for the video chip. You can probably
resolve this by increasing the I/O wait states in the RomWBW config file
when you create a custom ROM.

Post by RichLeary
A note on as-built configuration. I used all 74LS logic except for the
574's that are 74ALS574's just because I did not immediately find 74LS574's
at DigiKey, my preferred source. CPU oscillator is 18.432 MHz. Since I have
no plans to use the ECB interface I have not set the K1 configuration -
there is no jumper on K1. K21 & K22 are set to 1-2 jumpered but the two
4700 ohm resistors are still in place - without anything connected to the
ECB bus this should also be a "don't care".
Rich Leary