Samsung KS57C2308 manual Data Memory RAM

KS57C2308/P2308/C2316/P2316 ADDRESS SPACES

DATA MEMORY (RAM)

OVERVIEW

In its standard configuration, the 512 x 4-bit data memory has four areas:

—32 × 4-bit working register area in bank 0

—224 × 4-bit general-purpose area in bank 0 which is also used as the stack area

—224 × 4-bit general-purpose area in bank 1

—32 × 4-bit area for LCD data in bank 1

—128 × 4-bit area in bank 15 for memory-mapped I/O addresses

To make it easier to reference, the data memory area has three memory banks — bank 0, bank 1 and bank 15. The select memory bank instruction (SMB) is used to select the bank you want to select as working data memory. Data stored in RAM locations are 1-, 4-, and 8-bit addressable. One exception is the LCD data register area, which is 1-bit and 4-bit addressable only.

Initialization values for the data memory area are not defined by hardware and must therefore be initialized by program software following power RESET. However, when RESET signal is generated in power-down mode, the most of data memory contents are held.

000H		WORKING REGISTERS
					(32 x 4 Bits)
01FH
020H		GENERAL-PURPOSE						BANK 0
			REGISTERS AND
				STACK AREA
				(224 x 4		Bits)
0FFH
100H		GENERAL-PURPOSE
				REGISTERS
				(224 x 4		Bits)
								BANK 1
1DFH
1E0H		LCD DATA REGISTERS
					(32 x 4	Bits)
1FFH
F80H	~						~
		MEMORY-MAPPED I/O
		AEERESS REGISTERS						BANK 15
				(128 x 4 Bits)
FFFH

Figure 2-3. Data Memory (RAM) Map

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