[Openocd-development] Question on V850 from NEC

[Michel Catudal]

A MIPS question for those who know. Is there a usefull debug module in
the NEC V850? I would think that it would have at least the standard
MIPS module.
Am I wrong to think that? According to NEC and IAR the only way to debug
is to use the minicube.

Michel

[Xiaofan Chen]

Post by Michel Catudal
A MIPS question for those who know. Is there a usefull debug module in
the NEC V850? I would think that it would have at least the standard
MIPS module.
Am I wrong to think that? According to NEC and IAR the only way to debug
is to use the minicube.

I do not know much about V850. Are you suggesting that V850
and MIPS core have some relations? Google does not suggest
this...

[Michel Catudal]

Post by Xiaofan Chen

Post by Michel Catudal
A MIPS question for those who know. Is there a usefull debug module in
the NEC V850? I would think that it would have at least the standard
MIPS module.
Am I wrong to think that? According to NEC and IAR the only way to debug
is to use the minicube.

I do not know much about V850. Are you suggesting that V850
and MIPS core have some relations? Google does not suggest
this...

It might not be or is derived from one. I asked the question because I
was told at one time by a salesman that it was a MIPS

That line might give the implication that it is some sort of mips device.

/usr/lib/gcc-lib/mips-linux-gnu/2.95.4/include/va-v850.h

But from this site it appears to be an NEC design

http://www.nec.co.jp/press/en/9708/2801.html

Their JTAG interface is called N-WIRE

Their devices are about the best I have seen as far as embedded devices
are. Look at the V850ES though for the current ones.


For interrupt access
An ARM7TDMI takes 24 cycles to get to an interrupt
A Cortex-M3 takes 12 cycles to get to an interrupt
A V850E takes 4 cycles to get to an interrupt

As far as speed, at 32Mhz V850E is close to twice the speed of a
Micronas ARM7TDMI at 48Mhz.

I had never thought about looking at these devices until we were forced
to do so by Micronas screwing us by discontinuing their ARM7TDMI flash
devices.
I am very impressed by their Dashboard (Cluster) and Body devices (2 to
6 CAN available and price is very good)

The NEC programmer is only $100 but it is serial. The debugging is
N-WIRE (JTAG) and requires a device for debugging ($250-$500). I was
wondering if anyone
is familiar with these processors internals to know if the internal
debugging module has enough so we could do some debugging without
needing the outside device.

Some devices can be bought at relatively low price for personal designs,
so it is not just for us in the automotive industry.
http://www.futureelectronics.com/en/Search.aspx?dsNav=Ntk:PartNumberSearch|V850|1|,Ny:True,Nea:True

They are well known for having good prices for small 8 bit devices

http://www.futureelectronics.com/en/Technologies/Product.aspx?ProductID=UPD78F9202MACACANEC2877710


Michel

[Xiaofan Chen]

Post by Michel Catudal
Some devices can be bought at relatively low price for personal designs,
so it is not just for us in the automotive industry.
http://www.futureelectronics.com/en/Search.aspx?dsNav=Ntk:PartNumberSearch|V850|1|,Ny:True,Nea:True

I've seen a few designs with NEC V850 (Mini PLCs).

Post by Michel Catudal
They are well known for having good prices for small 8 bit devices
http://www.futureelectronics.com/en/Technologies/Product.aspx?ProductID=UPD78F9202MACACANEC2877710

I've the luxury to read some assembly codes of NEC17k 4-bit
OTP/Masks MCUs. NEC was suggesting us to go for their 78K
8-bit. But in the end I replaced them with Microchip PIC16 in
a simple but important design (EEx explosion proof Automation
market: a transformer isolated barrier which is the bread and
butter for the company). That was back in 1999 in my previous job.
At that time, NEC documentation is quite bad. Their emulator was
very expensive. NEC chips seemed to be ok then. Luckily I
chose Microchip and not Atmel AT90S AVR since Atmel obsoleted
all the AT90S AVR over the years and the product needs to be
in the market for 10-15 years at 100k-200k per year.

[Michel Catudal]

Post by Xiaofan Chen

Post by Michel Catudal
Some devices can be bought at relatively low price for personal designs,
so it is not just for us in the automotive industry.
http://www.futureelectronics.com/en/Search.aspx?dsNav=Ntk:PartNumberSearch|V850|1|,Ny:True,Nea:True

I've seen a few designs with NEC V850 (Mini PLCs).

NEC is very big in the US automotive industry and is a major player
here. They have foundries in many places around the world.
The funny part with most of our American company is that to same money
they have moved the production outside to low cost labor countries.
NEC has build big in the USA and move some production here. They have
won the hearts and minds of a lot of American Engineers.

Post by Xiaofan Chen

Post by Michel Catudal
They are well known for having good prices for small 8 bit devices
http://www.futureelectronics.com/en/Technologies/Product.aspx?ProductID=UPD78F9202MACACANEC2877710

I've the luxury to read some assembly codes of NEC17k 4-bit
OTP/Masks MCUs. NEC was suggesting us to go for their 78K
8-bit. But in the end I replaced them with Microchip PIC16 in
a simple but important design (EEx explosion proof Automation
market: a transformer isolated barrier which is the bread and
butter for the company). That was back in 1999 in my previous job.
At that time, NEC documentation is quite bad. Their emulator was
very expensive. NEC chips seemed to be ok then. Luckily I
chose Microchip and not Atmel AT90S AVR since Atmel obsoleted
all the AT90S AVR over the years and the product needs to be
in the market for 10-15 years at 100k-200k per year.

The nice thing with NEC is that they don't discontinue parts as do other
company. They still provide you with 4 bits or 8 bits
devices if you need them even when the parts no longer officially exist.
If you have a design with their devices they will provide
you with parts as long as you are willing to pay for them.

This is very important for us for military and automotive designs
because they doesn't want any change when a product works.

Companies bad for pulling parts of the market are Freescale and Hitachi
(now Renesas).

NEC and ST are two companies who have made serious profits last year
while companies like NXP, Infineon and Freescale have huge debts.

Michel

[Michel Catudal]

Post by Xiaofan Chen
At that time, NEC documentation is quite bad. Their emulator was
very expensive. NEC chips seemed to be ok then. Luckily I
chose Microchip and not Atmel AT90S AVR since Atmel obsoleted
all the AT90S AVR over the years and the product needs to be
in the market for 10-15 years at 100k-200k per year.

They have since moved to all flash and use JTAG debugging which they
call N-WIRE.

NEC's documentation is not easily available but once you are a customer
you get a lot more than most people get.
It is not as bad as TI which we had so sign non disclosure agreement
with. NEC doesn't really care, I think the problem is that most
of the good documentation is on the European site. I have suggested to
have that changed and make some links so that would
be transparent and was told that it was a good idea. There is no sense
to have data duplicated in different sites around the world
when each site can be accessed from anywhere in the world. The problems
though is that people here in the USA do not think
about looking at European or Asians sites and assume that documentation
of their devices is not available.
Most data that I have seem to have been translated in Germany. For a
while all I had was in Japanese and I was using a translator site.
When I complained to NEC they provided me with a link to a site in
Europe. Thev V850E devices that I am looking at using have been
out for a couple of years.

Michel

[Duane Ellis]

Post by Michel Catudal
A MIPS question for those who know. Is there a usefull debug module in
the NEC V850? I would think that it would have at least the standard
MIPS module.
Am I wrong to think that? According to NEC and IAR the only way to debug
is to use the minicube.
Michel

I doubt the V850 would ever be supported by openocd. Reason: Support for
it in GCC is long dead (dormant?), along with support for it in GDB,
those two things have to come first.

-Duane.

[Michel Catudal]

Post by Duane Ellis
I doubt the V850 would ever be supported by openocd. Reason: Support
for it in GCC is long dead (dormant?), along with support for it in
GDB, those two things have to come first.
-Duane.

The V850E is the latest and the latest GCC is working relatively well
from my tests. I will test it with the minicube in a few weeks and make
some comparisions
with NEC and IAR. I created the binaries for V850E so I could learn more
about that device that I am seriously looking into using for a new design.
I I use it I will likely buy the NEC or IAR Compiler.

Support for it would require to use the minicube if I am not mistaken as
from my talks with NEC the debug part is there.
It would require some reverse engineering because I doubt very much that
NEC would release information on it.
This is a lot of work. I wasn't asking if there was support planned, I
was just curious about their N-WIRE interface and as to what is in the
processor.

Michel