Author Topic: looking for a rom/ram emulator  (Read 13836 times)

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Offline legacy

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Re: looking for a rom/ram emulator
« Reply #25 on: October 04, 2014, 07:46:17 am »
The Ostrich's works OK for ROM emulation but have some limitations when tracing. Getting 2 Ostriches syncronised and tracing can be a bit of an issue.

But it is fast, usb driven (by libusb, on the linux user land side). Unfortunately it is expensive and ROM only. The trace feature is not working, bugged in software.

You neglected to mention how fast your target bus speed is, but I assume it's pretty slow.

120nsec time access

I used a FTDI USB serial to parallel chip for comms.

which FTDI chip ? 2232 ? Can i see something ?
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Offline skyline_stu

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Re: looking for a rom/ram emulator
« Reply #26 on: October 04, 2014, 05:24:32 pm »
Yes, the Ostrich is fast, a 27010 loads in about 4 seconds. Actually, I feel the bug is in the Ostrich hardware/firmware, not the PC end. It doesn't reliably trigger on the bit masks you send to the emulator.

I used a FTDI245R based board. They are inexpensive (no more than $20) and easy to use. There are 4 pins to monitor with your embeded software or hardware.

They are fast - 1Mbyte / sec and have a decent FIFO buffer 128byte RX, 256 byte TX

I send out the data in an 8 bit stream and have the emulator h/w re-assemble it to 16 bits.

My emulator is pretty simple in it's operation. The Micro waits for a control command, like download/upload data, base address and trace window size.  Uploads to the emulator are performed with the target power off - otherwise there will be contention and this really slows things down.

There are several SRAM's banks in the design. Some monitor reads, some writes and the corresponding data. The address bus is common to all devices, as well as being under micro & cpld control.

When I'm tracing, I send a command to repeatedly scan through the trace region and see if there have been hits in the desired region (i.e. $2000-$20FF).
This is performed by using another SRAM, When a system bus write is performed, the HIT buffer (which is initially cleared to $00) changes to $01, and the corresponding write value is placed in a dedicated write SRAM buffer. If there was a hit, the micro sends out a block of data with the raw address (a hex value from $0-$FF) and the data as a raw hex value. The PC end determines the address by adding the base address + offset (from the HIT buffer). The s/w then marks the area RED (write) and updates the value.  For a read, a block toggles to GREEN.

There are 2 SRAM 'system' banks, they are mirrored copy of the other, unless a value has been changed. The CPLD and micro control which is accessed, swapping when the RAM is disabled. (using the target _CE  line and a system CS pin). The micro then updates the other bank until another change is done.

Doing it this way reduces the processing overheads and improves trace speed. Obviously the micro & cpld monitors the R/W - _CE and/or _WR/_OE lines depending on where your trace region is, and does the update and swap when the chip is not selected.

You may find 16 bit SRAMS easier to use due to their larger size. In that case, you'd just need to select the upper or lower 8 bytes of data. :)

Break your design up into blocks and it will be a lot easier to implement.
 

Offline marmad

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Re: looking for a rom/ram emulator
« Reply #27 on: November 05, 2014, 07:54:22 am »
Just saw this thread, so I don't know if you've already bought a Moates or built something. It's been awhile since I needed to emulate parallel EPROM/RAM chips, but I need to do it again for some old devices, so I'm throwing together some parts to hack onto an old Xeltek programmer.

If you just need emulation but don't really require complex tracing (which, for me, is the majority of the time), it's quite easy to turn any existing USB EPROM programmer into an emulator for a couple of bucks worth of parts and a couple of hours of time; this allows you to skip both spending much time on hardware as well as having to develop any software. If you want to get clever, you can tap into some of the programmer's routines to simulate some trace-like features.
 

Offline legacy

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Re: looking for a rom/ram emulator
« Reply #28 on: November 05, 2014, 12:26:32 pm »
i have bought the Moates for 90 euro, i got it on ebay as second hand, i was lucky  :scared:

i have converted the Moates into an Ethernet ROM emulator using an embedded-linux board called 'arietta G25", sold by ACME System for $30. I have put everything into a pretty plastic box and it works very fast with a 100Mbit/sec lan an EHCI usb host!

i am also been developing an emulator by myself using a pretty ARM chip that has a built-in usb (i bought it from Olimex for $20), and i am designing the interface with also a level shifter 3.3V/5V stage; hopefully and considering my free time and everything i have scheduled to be done in my free time, the first board should be ready for february..march 2015

the target that needs an rom to be emulated is a pretty 68060 board which has an eprom of 512Kbyte on it  :-+
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Offline marshallh

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Re: looking for a rom/ram emulator
« Reply #29 on: November 05, 2014, 01:04:40 pm »
Cyclone III + 2mbit SRAM + FT245?
Verilog tips
BGA soldering intro

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Offline legacy

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Re: looking for a rom/ram emulator
« Reply #30 on: November 06, 2014, 12:28:19 am »
ARM chip with builtin USB + cpld + level-shifter
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Offline solac

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Re: looking for an rom/ram emulator
« Reply #31 on: October 05, 2015, 03:20:37 pm »


Around the CPU/whatever you need to isolate the eprom/ram to the target socket. Just a bit of 245 buffer arounds.

Btw, i have found this project that clarifies the concept. This project seems in use for something that deals with [i[pimp my ride car tuning[/i], also is seems using the same protocol used by Ostrich V2, which is a good points for its firmware. His authors claimed a "an ugly buy" somewhere in the circuit, be careful about that  :-//

hi sorry to revive and old thread. i was wondering if anyone has built this using the schematics ?
 

Offline legacy

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Re: looking for a rom/ram emulator
« Reply #32 on: October 06, 2015, 06:31:23 am »
not yet, after the "ARM chip with builtin USB + cpld + level-shifter" design (which works great), I have hacked a commercial ROM-emulator, and designed a custom RAM-emulator using Papilo/Pro + level shifters
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Offline commie

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Re: looking for a rom/ram emulator
« Reply #33 on: October 06, 2015, 09:13:24 am »
I bought this about year ago, used it once with success so far as I remember. Emulates up to 512k bytes roms.

http://uk.mouser.com/ProductDetail/EETools/EEROM-8U/?qs=%2fha2pyFadujQ4oaad2MGF7AB4v%252bBJJb9qocvcQuRPzaBOuwuz7FGwzIv3GOkcmmY
 

Offline legacy

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Re: looking for a rom/ram emulator
« Reply #34 on: October 06, 2015, 09:52:28 am »
Emulates up to 512k bytes roms.

how fast is it ? and is the protocol documented ?
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Offline legacy

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Re: looking for a rom/ram emulator
« Reply #35 on: October 06, 2015, 09:55:31 am »
found the datasheet, which tells

2 1M Byte (8M bit) / sec download speed
4 Uses 1MB high speed memory for proper emulation: 15ns high speed SRAM

OK, what about the protocol ?
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Offline free_electron

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Re: looking for a rom/ram emulator
« Reply #36 on: October 06, 2015, 10:02:02 am »
What protocol ? its a ram / eprom emulator. it emulates the classic static rams and parallel e/eeproms.
it can also dump the ram content and inverse assemble.

launch setup.exe. has really neat software.
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Offline legacy

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Re: looking for a rom/ram emulator
« Reply #37 on: October 06, 2015, 10:02:26 am »
(some time ago, I opened this topic about the same ROMemu, forgotten because I did not find informations about the protocol, and I had no time to reverse it)
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Offline legacy

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Re: looking for a rom/ram emulator
« Reply #38 on: October 06, 2015, 10:12:12 am »
Code: [Select]
# EEo
uart.fd3 /dev/ttyUSB0 at 921600bps, opened
"EpromEmulator-v1"
ans=(1)

# srecLO cavia.s19
loading SREC file into EEram … done, 131200 byte
ans=(1)

# EEw
mem_write(131200)
bulk addr=0x100, size=65536
bulk addr=0x10100, size=65536
bank addr=0x20100, size=128
ans=(1)

# EEc
uart.fd3 closed
ans=(1)

#

that is the interface of my ROM/emu (the first one I made with an ARM MPU + CPLD), the software is running in this board (ARM/linux), it talks uart over usb-bulk-driven, and I can't believe it is working damn fast:  at ~1Mbit/sec, 2 Banks of 64Kbyte have been written in a whistle  :o :o :o

I made a few boards but I do not have the effort to make other boards for my customers, so I prefer to recycle an existing product, but the software must run in a SoC/MIPS board.
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Offline commie

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Re: looking for a rom/ram emulator
« Reply #39 on: October 06, 2015, 10:12:08 pm »
c'on man, the USB protocol !!! I neet to attach it to a Linux/MIPS SoC, there is no Windows/x86 inside

Sorry Legacy, I'm using Windows XP and it works with that, but I do not know whether it will work with Linux.

It has the capacity to go to 1Megbyte but you need a special adapter, with the adapters supplied , 512kbyte max.
 

Offline free_electron

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Re: looking for a rom/ram emulator
« Reply #40 on: October 07, 2015, 07:30:11 am »
What protocol ? its a ram / eprom emulator

c'on man, the USB protocol !!! I neet to attach it to a Linux/MIPS SoC, there is no Windows/x86 inside
does that matter ? the target system is irrelevant. if your MIPS machine has a socket for an Eprom it will work. the OS / CPU doesn't matter.
the emulator has a ram on board with some logic that makes it behave as an eprom. Load the image into the emulator and your MIPS machine is none the wiser. it doesn;t need access to USB. the USB port is for the host machine where you run the development environment.

Oh , wait .. you mean : you want to use this on a MIPS based machine using linux , cause that is your development box ? tough shit sherlock.  The prevalent dev hardware is a intel architecture running microsoft stuff. once in a while you may find some linux stuff on intel. But beyond that ? it's a VERY small world.... Things are developed for the market. like it or not , that is still 90% Wintel ...and a bit Lintel and maybe a tiny bit iOS. anything else is esoteric and you will have to resort to homebrew.

Elektor magazine made an eprom emulator in the mid 90's that was using a 62256 ram , some counters and hooked up to a standard printerport.
you would take the binary image of the rom and simply 'copy' it to LPT1.

you had to press a button on the emulator to 'reset it'. you could then simply use a dos command 'copy eprom.bin lpt1:' and that was it.
they later made an rs232 version

https://www.elektormagazine.com/magazine/elektor-200101/16948

https://www.elektormagazine.com/magazine/elektor-200101

with any luck you can still buy the circuit board. a few dollar for the PDF file and off you go. that may be your best shot.

here's another one (older) : http://www.davidprojects.net78.net/styled-2/index.html

i built several of the printerport ones. they were mades using SMd and used 74590 and 74593 dual counters that were expensive and hard to find at the time.



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Offline legacy

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Re: looking for a rom/ram emulator
« Reply #41 on: October 07, 2015, 09:17:03 am »
does that matter ? the target system is irrelevant.

In my case the target is the control board of the combustion engine of a car (automotive purpose).

cause that is your development box

because it's in the project constraints, and because  my customers need something like that, during our "tests" we need to use an embedded linux board, and this board should control the ROM/emulator, the whole should be embedded with it, and able to reprogram it on demand, there is a custom App that generates the rom, and this program needs to access data from the can bus, plus other data from fpga, there are two systems, linux and VxWorks, we have the full control of both, from the source code side.

Elektor magazine made an eprom emulator in the mid 90's that was using a 62256 ram , some counters and hooked up to a standard printerport.
you would take the binary image of the rom and simply 'copy' it to LPT1.

have you read what I have written ? I have already built three ROM emulators for hobby purposes, they are working with linux (see the above example, it's a control shell I have written, it's the simplest) but I do not have the convenience (1) use them for my customers (because of a lot of reasons), I prefer to consider the recycling of an existing product, adapting my software to it, so I am looking for a commercial product with a full documented USB protocol.

(1) I might propose my ROM emulators to the executive manager, I need his help (and his authorization) to build 4 thousand units, but in this case … they also have to pay my design (I am a consultant). These units should be shipped to our final customers in order to make them able to run their and our testes autonomously, providing data back to us, just through an internet socket (a tcp/ip application, which runs inside the linux board, has been already designed for that).
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Offline solac

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Re: looking for a rom/ram emulator
« Reply #42 on: October 07, 2015, 11:46:18 am »
Im no engineer, nor do i understand how code work. Was looking to build this for personal use. I have seen this device demonstration in youtube. It used xtronics protocol to connect to crome. I was wondering if the hex file in the hub works? If i could i would just buy a moates ostrich but they don't sell it locally from where i live, trying to get one would probably cost very much since tariffs are very high for electronics stuff.

I was also thinking of using dip through hole chips. Almost all of the chips are avaialble in through hole except the ftdi chip. Why was the schematic made with atmega16 and not atmega16u ? which has usb support? to eliminate the need for ftdi chip?
 

Offline free_electron

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Re: looking for a rom/ram emulator
« Reply #43 on: October 08, 2015, 07:36:40 am »
does that matter ? the target system is irrelevant.

In my case the target is the control board of the combustion engine of a car (automotive purpose).

cause that is your development box

because it's in the project constraints, and because  my customers need something like that, during our "tests" we need to use an embedded linux board, and this board should control the ROM/emulator, the whole should be embedded with it, and able to reprogram it on demand, there is a custom App that generates the rom, and this program needs to access data from the can bus, plus other data from fpga, there are two systems, linux and VxWorks, we have the full control of both, from the source code side.

Elektor magazine made an eprom emulator in the mid 90's that was using a 62256 ram , some counters and hooked up to a standard printerport.
you would take the binary image of the rom and simply 'copy' it to LPT1.

have you read what I have written ? I have already built three ROM emulators for hobby purposes, they are working with linux (see the above example, it's a control shell I have written, it's the simplest) but I do not have the convenience (1) use them for my customers (because of a lot of reasons), I prefer to consider the recycling of an existing product, adapting my software to it, so I am looking for a commercial product with a full documented USB protocol.

(1) I might propose my ROM emulators to the executive manager, I need his help (and his authorization) to build 4 thousand units, but in this case … they also have to pay my design (I am a consultant). These units should be shipped to our final customers in order to make them able to run their and our testes autonomously, providing data back to us, just through an internet socket (a tcp/ip application, which runs inside the linux board, has been already designed for that).

looks like you painted yourself in a bit of a corner...
the truth is that things like eprom emulators are all designed to work with a bit of driver software. and that will invariably be win/tel.

you may have a chance using an emulator that uses an rs232 link. you can always slap a usb->rs232 converter in front of it. those protocols will be open.
Try Emutec. they may have one that works for you
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Offline solac

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Re: looking for a rom/ram emulator
« Reply #44 on: October 13, 2015, 02:43:01 am »
hi need some help with the constrution of honda rtp. i replace the ft232bl with ft232rl since its whats available locally. i have checked the data sheet and it seems to be the same, and it does not need an external oscilator? Also i bought a ram with the same part number is62c256 problem is its 70ns would it make a lot of difference in terms of speed? im using all dip packages for the ic except for the resistors and passive capacitors.

thanks
 

Offline grantb5

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Re: looking for a rom/ram emulator
« Reply #45 on: November 25, 2018, 11:44:22 am »

have you read what I have written ? I have already built three ROM emulators for hobby purposes, they are working with linux (see the above example, it's a control shell I have written, it's the simplest) but I do not have the convenience (1) use them for my customers (because of a lot of reasons), I prefer to consider the recycling of an existing product, adapting my software to it, so I am looking for a commercial product with a full documented USB protocol.

FWIW there is one called the Momik MemSIM2 that is serial over USB and the protocol is available on Github I think. It's very inexpensive too which is nice.
 

Offline legacy

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Re: looking for a rom/ram emulator
« Reply #46 on: November 25, 2018, 02:07:27 pm »
"Quote from: free_electron on October 07, 2015, 07:30:11 am"

after 3 years  :-DD
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Offline technix

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Re: looking for a rom/ram emulator
« Reply #47 on: November 28, 2018, 04:07:57 pm »
"Quote from: free_electron on October 07, 2015, 07:30:11 am"

after 3 years  :-DD
I am now looking into building one myself for a few projects that needs bootstrapping. I need UNIX support so a bit of challenge here.

My general idea here is to build a small module that takes whatever source protocol and turn it into 3.3V SPI Flash. This way I can either just use a W25Q128 in DIP-8 or use a STM32L432 to emulate a SPI Flash.
 


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