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Chapter 31 External Bus
1.Overview of the External Bus Interface
1.3 I/O Pins
The I/O pins are external bus interface pins (Some pins have other uses).
The following lists the I/O pins for each interface:
● Ordinary bus interface
• A31 to A00, D31 to D00 (AD15 to AD00)
• CS0, CS1, CS2, CS3, CS4, CS5, CS6, CS7
• AS, SYSCLK, MCLK
• RD
• WR, WR0(UUB), WR1(ULB), WR2(ULB), WR3(ULB)
• RDY, BRQ, BGRNT
● Memory interface
• MCLK, MCLKE
• MCLKI (for SDRAM)
• LBA(=AS), BAA (for burst ROM/FLASH)
• SRAS, SCAS, SWE (=WR) (for SDRAM)
• DQMUU,DQMUL,DQMLU,DQMLL (for SDRAM (=WR0, WR1, WR2, WR3))
● DMA interface
• IOWR, IORD
• DACK0, DACK1
• DREQ0, DREQ1
• DEOP0, DEOP1
1.4 Register List
Figure 1-2 "List of External Bus Interface Registers" shows the registers used by the external bus interface:
