Propeller External EEPROM

Newzed

I have just completed the preliminary design for a piggyback EEPROM for the Propeller, a screen shot of which is attached.· The EEPROM is an
AT45DB041, a 4MB EEPROM arranged as 2048 pages of 264 bytes each.· It is page-write only and operates on 3VDC which is taken from the Propeller power supply.· The attachment is shown with the EEPROM jumpered to Pins 0-4.· However, pads are provided for jumpering to Pins 11-15 and Pins 16-20.· I wouldn't have the foggiest about how to write a SPIN program for the EEPROM but I can supply a Stamp program than runs it, which a user should be able to convert to Spin.

The piggyback is plugged into the Prop socket underneath the Propeller.· I have made several of these piggybacks for the Stamp but none for the Propeller.· The boards are made on my SuperMill, single sided, so if anyone is interested I'll give it a shot.· If you have any questions about the AT45, please ask.

Sid

Newzed

Well, I'm up to my glutinous maximus in aquatic reptiles again.· I have this piggyback EEPROM, which is just plugged into a breadboard at the moment, and I'm trying to figure out how to write and read it.

With my Stamp, I first write to the 264-byte buffer:

---

Write_DataBuffer:······ 'DO NOT modfiy shiftouts
'IF d = "I" OR d = "i" THEN GOSUB cont6
'IF d = "E" OR d = "e" THEN GOSUB cont7
PAUSE 100
b = b+ 1
LOW CS
SHIFTOUT Dout,Sclk,MSBFIRST,[noparse][[/noparse]Buffer_1_Write\8, dummy\15, BAddr\9]· 'Buffer_1_Write con $84
SHIFTOUT Dout,Sclk,MSBFIRST,[noparse][[/noparse]v1.lowbyte,v1.highbyte,v2.lowbyte,v2.highbyte, v3.lowbyte,v3.highbyte,b.lowbyte, b.highbyte]
HIGH CS
DEBUG "Buffer:",· crsrx, 9, DEC v1/10, ".", DEC1 v1, crsrx, 18,DEC v2/10, ".", DEC1 v2,crsrx, 27, DEC v3/10, ".", DEC1 v3, crsrx, 37, DEC b, crsrx, 44, DEC baddr, cr
LOW red
PAUSE 500

PAUSE 200
IF baddr = 256 THEN
baddr = 0
GOSUB writemain
Baddr = 0
GOTO main
ENDIF

BAddr = BAddr + 8
IF b = a THEN
GOSUB writemain
DEBUG cr, "Press any key to continue", cr
DEBUGIN com
GOTO start
ENDIF
PAUSE dly/60
GOTO main

---

If I stop writing to the buffer or if it is full, my program automatically writes the contents of the buffer to main memory:

---

WriteMain1:

LOW cs
PAUSE 10
SHIFTOUT Dout,Sclk,MSBFIRST,[noparse][[/noparse]Xferout\8]·· 'Xferout CON $83
PAUSE 10
SHIFTOUT Dout, Sclk, MSBFIRST, [noparse][[/noparse]0\4]
PAUSE 10
SHIFTOUT Dout, Sclk, MSBFIRST, [noparse][[/noparse]PAddr\11]
PAUSE 10
SHIFTOUT Dout, Sclk, MSBFIRST, [noparse][[/noparse]Dummy\9]
PAUSE 10
HIGH cs
PAUSE 500
DEBUG "Page ", DEC paddr, " written to main", cr, cr

baddr = 0
PAddr = Paddr + 1
RETURN

---

To read the main memory, I write:

ReadMain:

DEBUG cr, "Reading main", cr

IF a = 0 THEN
GOSUB atdata
ENDIF

cont1:
paddr = 0
DEBUG cr, "Reading page ", DEC PAddr, cr, cr
b = 0
byaddr = 0

ReadMain1:
b = b + 1

IF b>a THEN
GOTO start
ENDIF

LOW cs

SHIFTOUT Dout,Sclk,MSBFIRST,[noparse][[/noparse]$D2\8]······· 'Xferin con $D2-$E8 cont. read
SHIFTOUT Dout,Sclk,MSBFIRST,[noparse][[/noparse]0\4]········· 'reserved bits set to logical 0 per page 15
SHIFTOUT Dout,Sclk,MSBFIRST,[noparse][[/noparse]paddr\11]····· 'page to read
SHIFTOUT Dout,Sclk,MSBFIRST,[noparse][[/noparse]Byaddr\9]···· 'starting byte to read
SHIFTOUT Dout,Sclk,MSBFIRST,[noparse][[/noparse]Dummy\16]···· 'don't care bits
SHIFTOUT Dout,Sclk,MSBFIRST,[noparse][[/noparse]Dummy\16]···· 'don't care bits
SHIFTIN Din ,Sclk,MSBpre,[noparse][[/noparse]v1.lowbyte,v1.highbyte,v2.lowbyte,v2.highbyte, v3.lowbyte,v3.highbyte, b.lowbyte, b.highbyte]
HIGH cs

DEBUG· "Data:· ", DEC v1/10, ".", DEC1 v1,"···· ",· DEC v2/10, ".", DEC1 v2, "···· ", DEC v3/10, ".", DEC1 v3,"······· ",DEC b, cr

Byaddr = Byaddr + 8

IF Byaddr >256 THEN
DEBUG cr
Byaddr = 0
Paddr = Paddr + 1
DEBUG "Reading Page ", DEC paddr, cr, cr
GOTO readmain1
ENDIF

GOTO ReadMain1

---

Anyone feel like helping?· Need more info?

Sid

Direct Digital Labs

While you are at it you might as well use the 16-Megabit version (4 Megabytes) AT45DB161

Digikey PN AT45DB161D-SU-ND

-Dan