About The Updateable Attribute Memory - Adaptec SlimSCSI APA-1460 Technical Reference

APA-1460 SlimSCSI Technical Reference

About the Updateable Attribute Memory

The total size of the Attribute Memory is 8 KBytes, ranging from 0000h to 1FFFh. Inter-
nally, an EEPROM is used to meet design requirements. During the Attribute Memory
Read cycle, there is no difference from reading regular memory. During the write cycle, a
special escape sequence must be followed to enable the write operation (see ATMEL data
sheets).
Sample code to enable the chip write protection:
write_enable
push
push
push
mov
mov
mov
mov
mov
mov
mov
mov
pop
pop
pop
ret
write_enable
5-6
proc
es
bx
cx
ax, mapped_seg :select the segment
es, ax
bx, 1555h ; write AAh to 1555h
byte ptr es:[bx], 0aah
bx, 0aaah ; write 55h to 0AAAh
byte ptr es:[bx], 55h
bx, 1555h ; write A0h to 1555h
byte ptr es:[bx], 0a0h
cx
bx
es
endp
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APA-1460 SlimSCSI Technical Reference
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A Stock Number: 510671-00, Rev. A
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Print Spec Number: 492966-00, Rev. A
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Current Date: 8/22/94
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Page: 5-6 A
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ECN Date: 8/30/94
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