between CPU and MCU

[arhi]

Hi,

question .. some time ago I used to develop some hw with 8086 / 80186 CPU .. but, now I wonder if there is something "in between" CPU and MCU... to be more to the point, does microchip (or someone else) makes IC that

- has some basic MCU functions (AD/USART/I2C/SPI)
- do *not* have internal EPROM/RAM but uses external EPROM and RAM modules for "work"

for e.g. if I have a project that will require 64MB of "code" and 128MB of RAM to execute, low cpu usage (so it can be slow), and need to communicate with periferials via I2C/SPI in "old days" I would have to put CPU + EEPROM + RAM for the cpu operation, on top of that I would have to make "port mapers" that will occupy address space and that way I would communicate with periferials, now, is there something in between ? (some small amount of internally mapped memory that is 1 8bit port with hw usart/spi/i2c and address/data lines for the rest of it) ?

 

[ericgibbs]

hi,
The Z84C90 plcc device has a number peripheral functions and its compatible with the 8bit 8080/Z80 series of CPU [central processing unit]

The Z8 has some of these features

 

[arhi]

hi,
The Z84C90 plcc device has a number peripheral functions and its compatible with the 8bit 8080/Z80 series of CPU [central processing unit]

The Z8 has some of these features

Thanks, downloading dsheet right now

Ah my old friend zilog, I was hoping microchip had something (as I have microchip distributor in the neighborhood ) but I'll see what will suit my hobby better .. still rediscovering charms of electronics, had not used a soldering iron in over 10 years... so first few days I had to spend researching wth is rohs why they replaced most of old ic's with "lead free" .. etc .. then I found out that what "then" was the major problem (getting datasheets) is now 2 clicks away + I found this forum ... wiiiiii .. made a line follower in one weekend, now playing with something more complex .. hopefully it will be done soon (if my job allows it)

 

[kjennejohn]

Hi. Atmel and Philips make a line of processors that have a loooong list of capabilities. However, you can forget about 64/128MB of code and data space. You can reallistically expect 4kB to 128kB, with one series (Philip's P89c66x) capable of 8MB of external code and 8MB of external data space. Go to DigiKey(.com) and type "8051 adc uart" into their search window. Then get a cup of coffee and settle in for a long read through the data base. You should get something like 800 to a 1000 hits back. I say 8051 because that is what my employer had me look for recently. There is still lots of free code and several tools out there for this venerable old line from Intel. looks like everybody else picked up on this chip while Intel lost interest in it. Add "flash" to the search and the list gets shorter, but this gives you code memory you can program over and over.

If you want lots of peripherals on the cheap ($2.46 for 8kB of code space/$2.64 for 16kB) check out the Philips 89LPC952/954 at DigiKey. This thing has more goodies stuffed in it than a Thanksgiving turkey.

And there are plenty of Atmel 89C-series chips (and others) with FLASH available in a DIP40 package, with 4k to 32k of code space. Great for breadboarding. And I'm sure Microchip has their lineup as well.

End $.02.
kenjj

 

[arhi]

thanks kjennejohn,
thing is, for now, I'm pretty satisfied with pic's .. collected data is stored on a MMC card and later used on PC... but for some ideas I have (to do with object recognition) I need to do a lot of matrix calculation and that requires RAM .. lot of it .. adding a bunch of unoptimized code lead to "I need many MB for program and many MB for RAM" .. it is far from "I need it now" and more like "it might be fun to try" ... I used to be in love with 8051 but then switched from Intel to motorola .. that was long long time ago, and now, now I do what amuses me... as basically 99% of things I make one can get from china and pay 10% of what I spent only for parts ... so .. 2.46$ or 24.6$ .. not much difference the only difference is "how much it will amuse me" ... and from what you and ericgibbs wrote there is a lot of fun out there for me out there

thanks for the pointers .. I will go trough the list and check out the tools I can get and properties they have (hence level of amusement) and check out if I do or do not want to enter into some project with those

 

[Daniek]

I know some of the 18f series pics have an external memory interface although I'm not sure if they can address as much memory as you want..
check out the datasheet of 18fx8xxx.