Motorola MVME172 - Manual (Page 282)

4-46 Computer Group Literature Center Web Site
IP2 Chip
4
Local Bus to IndustryPack Addressing
The following sections provide examples that illustrate local bus versus
IndustryPack addressing for different IndustryPack spaces and
programmed port widths. Throughout the examples LBA refers to the local
bus address defined by LA<23-0>, and IPA refers to the IndustryPack
address. IPA<22-7> is the value on signal pins IPAD<15-0>/IPBD<15-0>
during the select state (these only apply to memory accesses); IPA<6-1> is
the value on signal pins IPA<6-1>; and IPA<0> is the value inferred by
IPBS1*, where IPA<0> is 0 if IPBS1* is asserted and 1 if IPBS1* is
negated.
8-Bit Memory Space
This example is for IP_a, where the IP_a memory space is programmed
with a base address of $00000000, a size of 4MB, and a port width of 8
bits. The relationship of the IndustryPack address to the local bus address
is: IPA=(LBA*2)+1.
LBA IPA Comments
$00000000 $000001
$00000001 $000003
$00000002 $000005
$00000003 $000007
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$003FFFFC $7FFFF9
$003FFFFD $7FFFFB
$003FFFFE $7FFFFD
$003FFFFF $7FFFFF