AMMC0XXA Datasheet, PDF (9/39 Pages) Advanced Micro Devices – 2, 4, or 8 Megabyte 5.0 Volt-only Flash Miniature Card

PRELIMINARY
Data Accesses
The Miniature Card has a 16-bit data bus that can
accommodate word or byte accesses. By individually
asserting CEL# and CEH#, a host can access either
byte. However, byte swapping (moving the high byte
data to the low byte) is not supported.
Figure 2 shows the connections between the host and
Miniature Card. The host system address lines range
from A0-A25, whereas the Miniature Card address
lines range from A0–A24. On the host, A0 and the
byte/word line are sent to a decoder and output to
CEL# and CEH# on the Miniature Card. These two bits
enable a single device for byte accesses and two
devices for word accesses, as shown by the decoder
truth table in Figure 2. Again, the Miniature Card
address lines do not receive input from host address bit
A0. In this document, all address references are card
addresses, unless otherwise noted. Table 4 shows the
read/write modes for Miniature Cards.
Host A25 A24 A23
Host Bus
A22 A21
60-Pad Connector
Card
A24*** A23*** A22*** A21** A20*
Card Bus
A0 Byte/Word
A2
A1
Decoder
Decoder Truth Table
Input
Output
A0 B/W CEL CEH#
0
0
0
0
0
1
0
1
1
0
0
0
1
1
1
0
A1
A0 CEL# CEH#
20975D-3
* Not connected on 2 Mbyte card
** Not connected on 2 and 4 Mbyte card
*** Not connected
Figure 2.
Host/Card Address Connections
AmMC0XXA
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