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CHAPTER 4 BUS INTERFACE
4.7
Program Examples for the External Bus
This section shows simple sample programs for operating the external bus.
I Specification example of a program for external bus operation
❍ Registers are set as follows:
•
Areas
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Area 0 (AMD0): 16 bits, normal bus, automatic wait - 0
•
Area 1 (AMD1): 16 bits, normal bus, automatic wait - 2
•
Area 2 (AMD32): 16 bits, normal bus, automatic wait - 1
•
Area 3 (AMD32): 16 bits, normal bus, automatic wait - 1
•
Area 4 (AMD4): 16 bits, DRAM, page size 256, 1CAS/2WE, with wait, CBR refresh
•
Area 5 (AMD5): 16 bits, DRAM, page size 512, 2CAS/1WE, without wait, CBR refresh
•
Other buses
•
Refresh (RFCR): Without wait, 1/8 setting
•
External pin (EPCR0): External RDY acceptance, BRQ, BGRNT arbitration
•
External pin (DSCR): DRAM pin setting
•
Little-endian (LER): Area 2
❍ Note the following points:
•
MD2 to MD0: 001. External vector: 16-bit mode
•
Set the same bus width for area 0, then set the mode register (MODR).
•
Set areas 1 to 5 so that they do not overlap each other.
Note:
This model does not support the DRAM control function and chip select output.
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