interfacing a old fashioned 2716-2764 eprom to prop chip
Hey guys has anyone here ever interfaced the older type erpoms 2716-2764,27256 I have a bunch of them I mean a bunch 20 of each at least and wanted to install some spin programs into one and then boot it from the prop as a stand alone configuration for an offsite control projects , if anyone has done it and is willing to share I would love to see some examples
I tried connecting with the 1K resistor deal to the data and address lines I burned a very simple blink led program to see if the prop would boot but no luck.
I tried connecting with the 1K resistor deal to the data and address lines I burned a very simple blink led program to see if the prop would boot but no luck.
Comments
Try waiting 2 microseconds after outputting the address and pulling CE and OE low before reading the eprom.
Try filling the chip with 10101010/01010101 so that the output pins toggle as you step through the addresses and see what you get.
Try using a cmos buffer connected to 5V for the address, data, and CE/OE pins
Leon
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Post Edited By Moderator (Chris Savage (Parallax)) : 1/22/2009 10:06:01 PM GMT
Hardware:
Connect eight pins (P0-P7 assumed) from the prop to D0-D7 of the 27xx through 1K resistors.
Connect one pin (P8 assumed) from the prop to the reset pin (11) of the 4040 through a 1K resistor.
Connect one pin (P9 assumed) from the prop to the clock pin (10) of the 4040 through a 1K resistor.
Software:
Set P0-P7 to inputs
Set P8-P9 to outputs
Set P11 low to reset the 4040
Wait 100 nsec
Set P11 high to allow counting
For count = 1 to sizeofeprom
Wait for 1 usec
Read data on P0-P7
Do what you want to do with the data
Set P10 high
Wait for 100 nsec
Set P10 low
Go to For count statement
For very old chips you may have to increase the waits in the loop. This should read a 4K eprom in less than 5 msec. If you have eproms larger than 4K you will need to add a second 4040 which will get you up to 16 megabytes.
Post Edited (kwinn) : 1/22/2009 11:41:46 PM GMT
Just one other thing One of the problems I am running into is making spin code readable for my burner I can load Ascii . or Bin files the problem I am having is I have nothing to compile spin output to a bin file? example take the simple LED blinking program when I save it from the spin editor it save it as a spin file if I try and burn that file to eprom I dont think its the right way the erpom burner software will load a spin file i.e"test.spin" but when you looked at the disasembled code it does not seem to be even close
maybe I can find a compiler for spin to turn it into bin. also I hate to bug you but do you know of any sample programs in either Prop or BS2 that would let me read the code into any of these chips"prop basic stamp2"??
Thanks again
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