4 Nov
2018
4 Nov
'18
7:37 a.m.
I have posted previously about a DEC Pro 350 I am trying to get working
again. At the moment it seems to be constantly resetting the CPU.
I have traced one possible path for the cause of this back to a NEC chip for
which I cannot find a datasheet. It is a 40-pin DIP it is marked "NEC Japan
8239K6 D7201C". All I have been able to find is more modern USB host
controllers.
Can anyone tell me what it is? It is marked E32 (on the left about half way
up) in this picture:
https://rjarratt.files.wordpress.com/2018/10/system-board-labelled.jpg
Thanks
Rob
4 Nov
4 Nov
7:41 a.m.
On Sun, Nov 4, 2018 at 12:37 PM Rob Jarratt via cctalk
<cctalk at classiccmp.org> wrote:
I have posted previously about a DEC Pro 350 I am trying to get working
again. At the moment it seems to be constantly resetting the CPU.
I have traced one possible path for the cause of this back to a NEC chip for
which I cannot find a datasheet. It is a 40-pin DIP it is marked "NEC Japan
8239K6 D7201C". All I have been able to find is more modern USB host
controllers.
Almost certainly a uPD7201 multi-protocol (asynchronous and synchronous)
serial chip. I have an NEC data book with it in if all else fails but a google
search for 'uPD7201 datasheet' (no quotes) found sites with the data sheet
to download as a .pdf file.
Quite why that should reset the machine is beyond me....
-tony
8:10 a.m.
-----Original Message-----
From: Tony Duell [mailto:ard.p850ug1 at gmail.com]
Sent: 04 November 2018 12:42
To: rob at jarratt.me.uk; Jarratt RMA <robert.jarratt at ntlworld.com>; General
Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>
Subject: Re: Datasheet for a NEC Chip in DEC Professional 350
On Sun, Nov 4, 2018 at 12:37 PM Rob Jarratt via cctalk
<cctalk at classiccmp.org> wrote:
I have been trying to find what is driving this path in the logic and this chip was the
only one I for which I couldn't identify the pins, but it seems that from this
datasheet (https://datasheet4u.com/datasheet-pdf-file/1098405/NEC/UPD7201/1) they are all
inputs and not outputs. So I need to look again for an output pin that is driving this
signal.
Thanks
Rob
I have posted previously about a DEC Pro 350 I am trying to get
working again. At the moment it seems to be constantly resetting the CPU.
I have traced one possible path for the cause of this back to a NEC
chip for which I cannot find a datasheet. It is a 40-pin DIP it is
marked "NEC Japan
8239K6 D7201C". All I have been able to find is more modern USB host
controllers.
Almost certainly a uPD7201 multi-protocol (asynchronous and synchronous)
serial chip. I have an NEC data book with it in if all else fails but a google
search for 'uPD7201 datasheet' (no quotes) found sites with the data sheet
to download as a .pdf file.
Quite why that should reset the machine is beyond me.... 
8:47 a.m.
A constant pulsing reset is usually a watchdog at play. Hardware watchdogs are usually
implemented in systems to reset everything should the system not meet one specific
criteria: eg cpu touch one memory address before X amount of time, or pcb voltage lower
than X volts, etc.
Watchdogs are also usually found as software routines executed by the cpu also looking for
specific conditions. These rarely issue a reset hardware signal, just restar the program.
Sent from my iPhone
On 4 Nov 2018, at 14:10, Rob Jarratt via cctalk
<cctalk at classiccmp.org> wrote:
-----Original Message-----
From: Tony Duell [mailto:ard.p850ug1 at gmail.com]
Sent: 04 November 2018 12:42
To: rob at jarratt.me.uk; Jarratt RMA <robert.jarratt at ntlworld.com>; General
Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>
Subject: Re: Datasheet for a NEC Chip in DEC Professional 350
On Sun, Nov 4, 2018 at 12:37 PM Rob Jarratt via cctalk
<cctalk at classiccmp.org> wrote:
I have been trying to find what is driving this path in the logic and this chip was the
only one I for which I couldn't identify the pins, but it seems that from this
datasheet (https://datasheet4u.com/datasheet-pdf-file/1098405/NEC/UPD7201/1) they are all
inputs and not outputs. So I need to look again for an output pin that is driving this
signal.
Thanks
Rob
I have posted previously about a DEC Pro 350 I am trying to get
working again. At the moment it seems to be constantly resetting the CPU.
I have traced one possible path for the cause of this back to a NEC
chip for which I cannot find a datasheet. It is a 40-pin DIP it is
marked "NEC Japan
8239K6 D7201C". All I have been able to find is more modern USB host
controllers.
Almost certainly a uPD7201 multi-protocol (asynchronous and synchronous)
serial chip. I have an NEC data book with it in if all else fails but a google
search for 'uPD7201 datasheet' (no quotes) found sites with the data sheet
to download as a .pdf file.
Quite why that should reset the machine is beyond me.... 
9:08 a.m.
I know that the Rainbow's AFU watchdog was the bane of my existence back in
the day... It would fire if interrupts were disabled too long.
Warner
On Sun, Nov 4, 2018 at 6:47 AM Eduardo Cruz via cctalk <
cctalk at classiccmp.org> wrote:
A constant pulsing reset is usually a watchdog at
play. Hardware watchdogs
are usually implemented in systems to reset everything should the system
not meet one specific criteria: eg cpu touch one memory address before X
amount of time, or pcb voltage lower than X volts, etc.
Watchdogs are also usually found as software routines executed by the cpu
also looking for specific conditions. These rarely issue a reset hardware
signal, just restar the program.
Sent from my iPhone
this chip
was the only one I for which I couldn't identify the pins, but it
seems that from this datasheet (
https://datasheet4u.com/datasheet-pdf-file/1098405/NEC/UPD7201/1) they
are all inputs and not outputs. So I need to look again for an output pin
that is driving this signal.
On 4 Nov 2018, at 14:10, Rob Jarratt via cctalk
<cctalk at classiccmp.org>
wrote:
> -----Original Message-----
> From: Tony Duell [mailto:ard.p850ug1 at gmail.com]
> Sent: 04 November 2018 12:42
> To: rob at jarratt.me.uk; Jarratt RMA <robert.jarratt at ntlworld.com>;
General
> Discussion: On-Topic and Off-Topic Posts
<cctalk at classiccmp.org>
> Subject: Re: Datasheet for a NEC Chip in DEC Professional 350
>
> On Sun, Nov 4, 2018 at 12:37 PM Rob Jarratt via cctalk
> <cctalk at classiccmp.org> wrote:
>>
>> I have posted previously about a DEC Pro 350 I am trying to get
>> working again. At the moment it seems to be constantly resetting the
CPU.
>>
>>
>>
>> I have traced one possible path for the cause of this back to a NEC
>> chip for which I cannot find a datasheet. It is a 40-pin DIP it is
>> marked "NEC Japan
>> 8239K6 D7201C". All I have been able to find is more modern USB host
>> controllers.
>
> Almost certainly a uPD7201 multi-protocol (asynchronous and synchronous)
> serial chip. I have an NEC data book with it in if all else fails but a
google
> search for 'uPD7201 datasheet' (no
quotes) found sites with the data
sheet
to
download as a .pdf file.
Quite why that should reset the machine is beyond me....
I have been trying to find what is driving this path in the logic and
Thanks
Rob
4:11 p.m.
-----Original Message-----
From: Eduardo Cruz [mailto:edcross at gmail.com]
Sent: 04 November 2018 13:47
To: rob at jarratt.me.uk; Rob Jarratt <robert.jarratt at ntlworld.com>; General
Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>
Cc: Tony Duell <ard.p850ug1 at gmail.com>
Subject: Re: Datasheet for a NEC Chip in DEC Professional 350
A constant pulsing reset is usually a watchdog at play. Hardware watchdogs
are usually implemented in systems to reset everything should the system
not meet one specific criteria: eg cpu touch one memory address before X
amount of time, or pcb voltage lower than X volts, etc.
Watchdogs are also usually found as software routines executed by the cpu
also looking for specific conditions. These rarely issue a reset hardware
signal,
just restar the program.
It looks to me like the reset is every 10us. I don't know how long the
watchdog is likely to be, the technical manual I have doesn't seem to
mention it in the section on the reset logic. I am still trying to find the
source of the signal that seems to be in the "wrong" state.
Regards
Rob
4:36 p.m.
Just had a look to this manual:
http://www.bitsavers.org/pdf/dec/pdp11/pro3xx/EK-PC350-TM-001_Professional_…
5.2.3.4 Power-Up Self-Tests, this section mentions the existence of rom
containing basic power up tests. I assume you are not even getting there
and your system fails to execute from this rom and report any errors on
screen?
In such case, A) is your cpu working? B) Is the rom code correct?
On Sun, Nov 4, 2018 at 10:11 PM Rob Jarratt <robert.jarratt at ntlworld.com>
wrote:
-----Original Message-----
From: Eduardo Cruz [mailto:edcross at gmail.com]
Sent: 04 November 2018 13:47
To: rob at jarratt.me.uk; Rob Jarratt <robert.jarratt at ntlworld.com>;
General
Discussion: On-Topic and Off-Topic Posts
<cctalk at classiccmp.org>
Cc: Tony Duell <ard.p850ug1 at gmail.com>
Subject: Re: Datasheet for a NEC Chip in DEC Professional 350
A constant pulsing reset is usually a watchdog at play. Hardware
watchdogs
are usually implemented in systems to reset
everything should the system
not meet one specific criteria: eg cpu touch one memory address before X
amount of time, or pcb voltage lower than X volts, etc.
Watchdogs are also usually found as software routines executed by the cpu
also looking for specific conditions. These rarely issue a reset hardware
signal,
just restar the program.
It looks to me like the reset is every 10us. I don't know how long the
watchdog is likely to be, the technical manual I have doesn't seem to
mention it in the section on the reset logic. I am still trying to find the
source of the signal that seems to be in the "wrong" state.
Regards
Rob
4:55 p.m.
There was a NEC CPU upgrade kit, one used to replace the stock CPU, is this
what you're talking about here? If so, I believe there was a battery that
went with the chip. If the battery is dead the chip would not work. Or am
I totally remember this wrong?
b
On Sun, Nov 4, 2018 at 4:36 PM Ed C. via cctalk <cctalk at classiccmp.org>
wrote:
Just had a look to this manual:
http://www.bitsavers.org/pdf/dec/pdp11/pro3xx/EK-PC350-TM-001_Professional_…
5.2.3.4 Power-Up Self-Tests, this section mentions the existence of rom
containing basic power up tests. I assume you are not even getting there
and your system fails to execute from this rom and report any errors on
screen?
In such case, A) is your cpu working? B) Is the rom code correct?
On Sun, Nov 4, 2018 at 10:11 PM Rob Jarratt <robert.jarratt at ntlworld.com>
wrote:
system
-----Original Message-----
From: Eduardo Cruz [mailto:edcross at gmail.com]
Sent: 04 November 2018 13:47
To: rob at jarratt.me.uk; Rob Jarratt <robert.jarratt at ntlworld.com>;
General
Discussion: On-Topic and Off-Topic Posts
<cctalk at classiccmp.org>
Cc: Tony Duell <ard.p850ug1 at gmail.com>
Subject: Re: Datasheet for a NEC Chip in DEC Professional 350
A constant pulsing reset is usually a watchdog at play. Hardware
watchdogs
> are usually implemented in systems to reset everything should the > not meet one specific criteria: eg cpu touch
one memory address before
X
> amount of time, or pcb voltage lower than X
volts, etc.
>
> Watchdogs are also usually found as software routines executed by the
cpu
> also looking for specific conditions. These
rarely issue a reset
hardware
signal,
the
just restar the program.
It looks to me like the reset is every 10us. I don't know how long the
watchdog is likely to be, the technical manual I have doesn't seem to
mention it in the section on the reset logic. I am still trying to find source of the signal that seems to be in the
"wrong" state.
Regards
Rob
5 Nov
5 Nov
9:24 p.m.
On 11/04/2018 08:10 AM, Rob Jarratt via cctech wrote:
Rob, you need to have the drawing for the PRO-350, and read it.? Reset
on the F11 chipset is generally part of
Pwr-OK? and if reset is bouncing likely power is NOT ok.?
FYI the 7201 is MPSC a dual multiprotocol serial chip not unlike the
Z80-SIO.? Likely the system wide reset
is coming from the power OK generation as you seeing hardware reset into
the MPSC.
Hint: the pro350 is basically an 11/23 in a different form factor.
Allison
-----Original
Message-----
From: Tony Duell [mailto:ard.p850ug1 at gmail.com]
Sent: 04 November 2018 12:42
To: rob at jarratt.me.uk; Jarratt RMA <robert.jarratt at ntlworld.com>; General
Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>
Subject: Re: Datasheet for a NEC Chip in DEC Professional 350
On Sun, Nov 4, 2018 at 12:37 PM Rob Jarratt via cctalk
<cctalk at classiccmp.org> wrote:
I have been trying to
find what is driving this path in the logic and this chip was the only one I for which I
couldn't identify the pins, but it seems that from this datasheet
(https://datasheet4u.com/datasheet-pdf-file/1098405/NEC/UPD7201/1) they are all inputs and
not outputs. So I need to look again for an output pin that is driving this signal.
Thanks
Rob
I have posted previously about a DEC Pro 350 I am
trying to get
working again. At the moment it seems to be constantly resetting the CPU.
I have traced one possible path for the cause of this back to a NEC
chip for which I cannot find a datasheet. It is a 40-pin DIP it is
marked "NEC Japan
8239K6 D7201C". All I have been able to find is more modern USB host
controllers.
Almost certainly a uPD7201 multi-protocol (asynchronous and
synchronous)
serial chip. I have an NEC data book with it in if all else fails but a google
search for 'uPD7201 datasheet' (no quotes) found sites with the data sheet
to download as a .pdf file.
Quite why that should reset the machine is beyond me....
6 Nov
6 Nov
2:18 a.m.
If you know where to find the printset for the 350 then please let me know.
In the absence of a printset i have been reverse engineering the schematic to work out the
cause of the resets, i am just having trouble tracing one possible path, and i am away all
week so can't look again until the weekend.
Thanks
Rob
Sent from my Windows 10 device
From: allison via cctech
Sent: 06 November 2018 02:24
To: cctech at classiccmp.org
Subject: Re: Datasheet for a NEC Chip in DEC Professional 350
On 11/04/2018 08:10 AM, Rob Jarratt via cctech wrote:
Rob, you need to have the drawing for the PRO-350, and read it.? Reset
on the F11 chipset is generally part of
Pwr-OK? and if reset is bouncing likely power is NOT ok.?
FYI the 7201 is MPSC a dual multiprotocol serial chip not unlike the
Z80-SIO.? Likely the system wide reset
is coming from the power OK generation as you seeing hardware reset into
the MPSC.
Hint: the pro350 is basically an 11/23 in a different form factor.
Allison
-----Original
Message-----
From: Tony Duell [mailto:ard.p850ug1 at gmail.com]
Sent: 04 November 2018 12:42
To: rob at jarratt.me.uk; Jarratt RMA <robert.jarratt at ntlworld.com>; General
Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>
Subject: Re: Datasheet for a NEC Chip in DEC Professional 350
On Sun, Nov 4, 2018 at 12:37 PM Rob Jarratt via cctalk
<cctalk at classiccmp.org> wrote:
I have been trying to
find what is driving this path in the logic and this chip was the only one I for which I
couldn't identify the pins, but it seems that from this datasheet
(https://datasheet4u.com/datasheet-pdf-file/1098405/NEC/UPD7201/1) they are all inputs and
not outputs. So I need to look again for an output pin that is driving this signal.
Thanks
Rob
I have posted previously about a DEC Pro 350 I am
trying to get
working again. At the moment it seems to be constantly resetting the CPU.
I have traced one possible path for the cause of this back to a NEC
chip for which I cannot find a datasheet. It is a 40-pin DIP it is
marked "NEC Japan
8239K6 D7201C". All I have been able to find is more modern USB host
controllers.
Almost certainly a uPD7201 multi-protocol (asynchronous and
synchronous)
serial chip. I have an NEC data book with it in if all else fails but a google
search for 'uPD7201 datasheet' (no quotes) found sites with the data sheet
to download as a .pdf file.
Quite why that should reset the machine is beyond me....
2087
days inactive
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9 comments
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allisonportable＠gmail.com -
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