KS57C2308/P2308/C2316/P2316 ADDRESS SPACES
2-5
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.
GENERAL-PURPOSE
REGISTERS AND
STACK AREA
(224 x 4 Bits)
WORKING REGISTERS
(32 x 4 Bits)
LCD DATA REGISTERS
(32 x 4 Bits)
MEMORY-MAPPED I/O
AEERESS REGISTERS
(128 x 4 Bits)
000H
01FH
020H
0FFH
100H
FFFH
1FFH
F80H ~~
BANK 0
BANK 1
BANK 15
GENERAL-PURPOSE
REGISTERS
(224 x 4 Bits)
1DFH
1E0H
Figure 2-3. Data Memory (RAM) Map