MT90883 Zarlink Semiconductor, MT90883 Datasheet - Page 66

• Manufacturer Part Number: MT90883
• Description: (MT90880 - MT90883) TDM to Packet Processors
• Manufacturer: Zarlink Semiconductor

Connecting to multiple external memory devices
The four devices are connected in banks, and the MT90880 device automatically switches to the next bank
when the address exceeds the range of the bank. Therefore the MT90880 needs to be informed during
initialisation which memory size is being used. This affects the number of active address signals and the total
available memory size, as shown in Table 17. Inactive address signals always output a low state.
Connection to the memory devices is identical to that for a single memory device (see Figure 29), except that
the four memory bank write enable signals, and the four memory bank output enable signals are connected to
each memory device in turn, e.g. RAM_WE[0]# to device 1, RAM_WE[1]# to device 2, etc. All other connections
and tie-offs are the same.
Table 29 - Total Available Memory Size, Using Four External SSRAM Devices
SSRAM size
16 Mbs
8 Mbs
4 Mbs
2 Mbs
1 Mbs
Total available capacity using 4 devices
Zarlink Semiconductor Inc.
MT90880/1/2/3
0.5 Mbytes
8 Mbytes
4 Mbytes
2 Mbytes
1 Mbytes
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Active address
signals
20:2
19:2
18:2
17:2
16:2
Data Sheet