Pages: 1 [2]   Go Down
Author Topic: More than 256K of memory?  (Read 3108 times)
0 Members and 1 Guest are viewing this topic.
SF Bay Area (USA)
Offline Offline
Tesla Member
***
Karma: 132
Posts: 6746
Strongly opinionated, but not official!
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

The classic 8051 processor contains 128 bytes of RAM.
But we're talking code space, aren't we?  PIC10F200 has 256 words of program and 16 bytes of "RAM" (and very few "registers, but it does have some hw stack.)  Atmel ATtiny4 has 256 words of program and 32 bytes of RAM, plus some registers.   In the AVR case, 256 words of program works out to 512 bytes; for the PIC10, an instruction word is only 12bits...
Logged

Global Moderator
Offline Offline
Brattain Member
*****
Karma: 481
Posts: 18742
Lua rocks!
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Atmel makes ATtiny processors with no SRAM.

Whoa.
Logged


Global Moderator
Offline Offline
Brattain Member
*****
Karma: 481
Posts: 18742
Lua rocks!
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

I withdraw that comment. The early processors (eg. 6800, 6502) had no RAM as such. But you wouldn't operate them without RAM on the bus.
Logged


Global Moderator
Dallas
Online Online
Shannon Member
*****
Karma: 206
Posts: 12861
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset


There is at least one Atmel AVR ATtiny processor with no SRAM.  The one I looked at has three "slots" for return addresses so CALL (barely) works but it otherwise has no memory.  All data has to be kept in registers (32 bytes) (or EEPROM).

Quote
Whoa.

No doubt!  "ATtiny" is apropo.
Logged

Anaheim CA.
Offline Offline
Faraday Member
**
Karma: 46
Posts: 2883
...
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Talk about the room being so small you had to go out side to change your mind...
Logged

--> WA7EMS <--
“The solution of every problem is another problem.” -Johann Wolfgang von Goethe
I do answer technical questions PM'd to me with whatever is in my clipboard

Show Your Work
Offline Offline
Edison Member
*
Karma: 14
Posts: 1098
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Since we are pressing on without the pleasure of the company of the OP, I was reading yesterday about how one of the first gaming consoles (or devices anyway) only had 128 bytes of RAM, because it was so expensive. It might have been Pong. So each frame refresh, the entire playing field had to be generated from scratch, because it couldn't be stored in RAM.

The Atari 2600 had no video memory.  The video signal out was generated on the fly.  This was not just pong, but for every game that ran on this system.  I think it generated an interrupt when a scanline needed to be started for output to the TV and then it was up to the CPU to provide the data on the fly.

http://en.wikipedia.org/wiki/Atari_2600

A lot of vector games worked this way too.  For vector monitors this makes total sense because the main program has control of the electron gun and doesn't even have the constraints of timing, except how many inches of line it can draw between refresh cycles.
« Last Edit: February 25, 2013, 04:51:20 pm by JoeN » Logged

I have only come here seeking knowledge. Things they would not teach me of in college.

Pages: 1 [2]   Go Up
Jump to: