ATTINY12 ATMEL Corporation, ATTINY12 Datasheet - Page 13

• Manufacturer Part Number: ATTINY12
• Description: 8-bit AVR Microcontroller with 1K Byte Flash
• Manufacturer: ATMEL Corporation

EEPROM Data Memory
Memory Access and
Instruction Execution
Timing
1006D–AVR–07/03
The ATtiny12 contains 64 bytes of data EEPROM memory. It is organized as a separate
data space, in which single bytes can be read and written. The EEPROM has an endur-
ance of at least 100,000 write/erase cycles. The access between the EEPROM and the
CPU is described on page 38, specifying the EEPROM Address Register, the EEPROM
Data Register, and the EEPROM Control Register.
For SPI data downloading, see “Memory Programming” on page 46 for a detailed
description.
This section describes the general access timing concepts for instruction execution and
internal memory access.
The AVR CPU is driven by the System Clock Ø, directly generated from the external
clock crystal for the chip. No internal clock division is used.
Figure 14 shows the parallel instruction fetches and instruction executions enabled by
the Harvard architecture and the fast-access register file concept. This is the basic pipe-
lining concept to obtain up to 1 MIPS per MHz with the corresponding unique results for
functions per cost, functions per clocks, and functions per power-unit.
Figure 14. The Parallel Instruction Fetches and Instruction Executions
Figure 15 shows the internal timing concept for the register file. In a single clock cycle,
an ALU operation using two register operands is executed and the result is stored back
to the destination register.
Figure 15. Single-cycle ALU Operation
Register Operands Fetch
2nd Instruction Execute
3rd Instruction Execute
1st Instruction Execute
ALU Operation Execute
2nd Instruction Fetch
3rd Instruction Fetch
4th Instruction Fetch
1st Instruction Fetch
Total Execution Time
Result Write Back
System Clock Ø
System Clock Ø
T1
T1
T2
T2
T3
ATtiny11/12
T3
T4
T4
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