Specifications

12
3706C–MICRO–2/11
AT89LP3240/6440
Figure 3-1. Program Memory Map
3.2 Internal Data Memory
The AT89LP3240/6440 contains 256 bytes of general SRAM data memory plus 128 bytes of I/O
memory mapped into a single 8-bit address space. Access to the internal data memory does not
require any configuration. The internal data memory has three address spaces: DATA, IDATA
and SFR; as shown in Figure 3-2. Some portions of external d
ata memory are also implemented
internally. See “External Data Memory” below for more information.
Figure 3-2. Internal Data Memory Map
3.2.1 DATA
The first 128 bytes of RAM are directly addressable by an 8-bit address (00H–7FH) included in
the instruction. The lowest 32 bytes of DATA memory are grouped into 4 banks of 8 registers
each. The RS0 and RS1 b
its (PSW.3 and PSW.4) select which register bank is in use. Instruc-
tions using register addressing will only access the currently specified bank. The lower 128 bit
addresses are also mapped into DATA addresses 20H—2FH.
Program Memory
0000
FFFF
0000
007F
User Signature Array
0100
01FF
Atmel Signature Array
SIGEN=0
SIGEN=1
AT89LP6440
Program Memory
0000
7FFF
0000
007F
User Signature Array
0100
01FF
Atmel Signature Array
AT89LP3240
FFH
UPPER
128
80H
7FH
LOWER
128
0
ACCESSIBLE
BY DIRECT
ADDRESSING
FFH
80H
ACCESSIBLE
BY DIRECT
AND INDIRECT
ADDRESSING
SPECIAL
FUNCTION
REGISTERS
PORTS
STATUS AND
CONTROL BITS
REGISTERS
STACK POINTER
ACCUMULATOR
(ETC.)
TIMERS
ACCESSIBLE
BY INDIRECT
ADDRESSING
ONLY
IDATA
SFR
DATA/IDATA