CHAPTER 3. FEATURES OF ARCHITECTURE AND MEMORY MAP

CHAPTER 3. FEATURES OF ARCHITECTURE AND MEMORY MAP

The μPD75402A’s architecture is a subset of the 75X architecture. Its features are outlined below.

3.1DATA MEMORY BANK CONFIGURATION AND ADDRESSING MODES

3.1.1Data Memory Bank Configuration

The μPD75402A’s data memory space has a bank configuration. Addresses 000H to 03FH of Bank 0 are a data area as shown in Table 3-1 and are built in with a static RAM (64 × 4 bits). Addresses F80H to FFFH of Bank 15 are a peripheral hardware area and are built in with the input/output port, serial interface, etc. To address this data memory space of a 12-bit address, the low-order 8-bit address is specified directly or indirectly by an instruction. The high-order 4-bit address is determined by the memory bank (MB) to be accessed.

The μPD75402A is built in with only Memory bank 0 and 15 and does not require bank switching unlike other products of the 75X series. The memory bank to be accessed is determined by the addressing mode and the address to be specified (see Tables 3-1 and 3-2).

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NEC PD75P402, PD75402A user manual Features of Architecture and Memory MAP, Data Memory Bank Configuration