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# ACER AMERICA CORPORATION
HMB-16/20
Card Type Memory
Chipset/Controller N/A
I/O Options None
Maximum DRAM 8MB (4MB on HPB supplemental memory card)
IMG IMG 1
+------------------------------------------------------------+
| STARTING ADDRESS |
|------------------------------------------------------------|
| Address | JP1 |
|-------------------------------+----------------------------|
| 1.25MB (1MB system RAM) | Pins 1 & 2 closed |
|-------------------------------+----------------------------|
| 4.25MB (4MB system RAM) | Pins 2 & 3 closed |
+------------------------------------------------------------+
+------------------------------------------------------------+
| PARITY CHECK |
|------------------------------------------------------------|
| Enabled | JP2 |
|----------------------------+-------------------------------|
| » | Enabled | Pins 2 & 3 closed |
|---+------------------------+-------------------------------|
| | Disabled | Pins 1 & 2 closed |
+------------------------------------------------------------+
+------------------------------------------------------------+
| MEMORY SIZE |
|------------------------------------------------------------|
| Size | SW1/1 | SW1/2 | SW1/3 |
|---------------+--------------+--------------+--------------|
| 2MB | On | On | On |
|---------------+--------------+--------------+--------------|
| 4MB | Off | On | On |
|---------------+--------------+--------------+--------------|
| 6MB | Off | Off | On |
|---------------+--------------+--------------+--------------|
| 8MB | Off | Off | Off |
+------------------------------------------------------------+
+------------------------------------------------------------+
| MEMORY READ/WRITE TIMING |
|------------------------------------------------------------|
| Card Model/System Speed | SW1/4 | TP1 |
|--------------------------+-------+-------------------------|
| » | HMB-16/100-ns | On | Pins 4 & 9, 3 & 8 |
| | | | closed |
|-------+------------------+-------+-------------------------|
| » | HMB-20/85-ns | On | Pins 4 & 9, 1 & 6 |
| | | | closed |
|-------+------------------+-------+-------------------------|
| | HMB-16/85-ns | Off | Pins 4 & 9, 3 & 9 |
| | | | closed |
|-------+------------------+-------+-------------------------|
| | HMB-20/100-ns | On | Pins 4 & 9, 1 & 6 |
| | | | closed |
|------------------------------------------------------------|
| Note: SW1/4 in the on position enables the zero wait |
| state. |
+------------------------------------------------------------+
+------------------------------------------------------------+
| DRAM CONFIGURATION |
|------------------------------------------------------------|
| Size | Bank 0 | Bank 1 | Bank 2 | Bank 3 | Parity |
| | | | | | Bits |
|--------+----------+----------+---------+---------+---------|
| 2MB | (16) | None | None | None | (8) |
| | 514256 | | | | 511000 |
|--------+----------+----------+---------+---------+---------|
| 4MB | (16) | (16) | None | None | (8) |
| | 514256 | 514256 | | | 511000 |
|--------+----------+----------+---------+---------+---------|
| 6MB | (16) | (16) | (16) | None | (8) |
| | 514256 | 514256 | 514256 | | 511000 |
|--------+----------+----------+---------+---------+---------|
| 8MB | (16) | (16) | (16) | (16) | (8) |
| | 514256 | 514256 | 514256 | 514256 | 511000 |
|------------------------------------------------------------|
| Note:(1) Banks 2 & 3 are located on the HPB daughter card. |
|------------------------------------------------------------|
| (2) The HMB-16 uses 100-ns 514256 RAM chips and 100-ns |
| 511000 parity chips. |
|------------------------------------------------------------|
| (3) The HMB-20 uses 85-ns 514256 RAM chips and 85-ns |
| 511000 parity chips. |
+------------------------------------------------------------+
+------------------------------------------------------------+
| MISCELLANEOUS TECHNICAL NOTES |
|------------------------------------------------------------|
| The HMB-16/20 is for use only in Acer interleaved-memory |
| systems. |
+------------------------------------------------------------+