
20
7674F–AVR–09/09
ATmega164P/324P/644P
The 32 general purpose working registers, 64 I/O registers, 160 Extended I/O Registers and the
1024/2048/4096 bytes of internal data SRAM in the ATmega164P/324P/644P are all accessible
Figure 6-2.
Data Memory Map
6.3.1
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 6-3.
On-chip Data SRAM Access Cycles
32 Registers
64 I/O Registers
Internal SRAM
(1024/2048/4096 x 8)
$0000 - $001F
$0020 - $005F
$10FF
$0060 - $00FF
Data Memory
160 Ext I/O Reg.
$0100
clk
WR
RD
Data
Address
Address valid
T1
T2
T3
Compute Address
Read
Wr
ite
CPU
Memory Access Instruction
Next Instruction