
21
8272E–AVR–04/2013
ATmega164A/PA/324A/PA/644A/PA/1284/P
The 32 general purpose working registers, 64 I/O registers, 160 Extended I/O Registers and
th e 1 02 4/2 0 4 8 /4 09 6 b yte s of inte rn al d a ta SRAM in t h e A tme l
ATmega164A/164PA/324A/324PA/644A/644PA/1284/1284P are all accessible through all these
Figure 8-2.
Data Memory Map for
ATmega164A/164PA/324A/324PA/644A/644PA/1284/1284P.
8.3.1
Data memory access times
This section describes the general access timing concepts for internal memory access. The
internal data SRAM access is performed in two clk
Figure 8-3.
On-chip data SRAM access cycles.
32 Registers
64 I/O Registers
Internal SRAM
(1024/2048/4096/16384x 8)
0x0000 - 0x001F
0x0020 - 0x005F
0x04FF/0x08FF/0x10FF/0x40FF
0x0060 - 0x00FF
Data Memory
160 Ext I/O Reg.
0x0100
clk
WR
RD
Data
Address
Address valid
T1
T2
T3
Compute Address
Read
Wr
ite
CPU
Memory Access Instruction
Next Instruction