M16C User Manual.pdf

External BusesMitsubishi microcomputersM16C / 62 GroupSINGLE-CHIP 16-BIT CMOS MICROCOMPUTER(1)4-Mbyte ROM and 128-Kbyte SRAM Connection ExampleFigure 5.3.6 shows how to connect 4-Mbyte ROM and 128-Kbyte SRAM in microprocessor mode. Locate_______the 4-Mbyte ROM in the CS0 area that has been extended in memory space extension mode 2 and the______128-Kbyte SRAM in the CS2 area.CNVssBYTECS0CS1CS2CS3A0 to A19A16toA0CS2CS0RDWRA16toA0S1S2OEWDQ1toDQ8D0toD7CS3CS2CS1A19A17 to A0CS0RDA21A20A19A18A17 to A0DQ0CE toOE DQ7D0toD7128K bytes SRAM4M bytes ROMRDWRD0 to D7M16C/62Figure 5.3.6. 4-Mbyte ROM and 128-Kbyte SRAM Connection ExampleConnect CS0 to the 4-Mbyte ROM’s chip enable pin and CS1, CS2, and CS to the address pins A19, A20,and A21, respectively. Connect the M16C’s A19 to the 4-Mbyte ROM’s A18, leaving the M16C’s A18unused.In the above diagram, an SRAM with two chip select signal inputs is used. When using memory with onlyone chip select signal input, you need to have an external circuit to decode the address.Addresses in 4-Mbyte ROM with regard to M16C settings are shown in Table 5.3.1.____________517