Atmel ATtiny85 User Manual

145
7598H–AVR–07/09
ATtiny25/45/85
21.8.4 Programming the Flash
The Flash is organized in pages, see Table 21-10 on page 140. When programming the Flash,
the program data is latched into a page buffer. This allows one page of program data to be pro-
grammed simultaneously. The following procedure describes how to program the entire Flash
memory:
1. Load Command “Write Flash” (see Table 21-16).
2. Load Flash Page Buffer.
3. Load Flash High Address and Program Page. Wait after Instr. 3 until SDO goes high for
the “Page Programming” cycle to finish.
4. Repeat 2 through 3 until the entire Flash is programmed or until all data has been
programmed.
5. End Page Programming by Loading Command “No Operation”.
When writing or reading serial data to the ATtiny25/45/85, data is clocked on the rising edge of
the serial clock, see Figure 21-6, Figure 21-7 and Table 21-17 for details.
Figure 21-5. Addressing the Flash which is Organized in Pages
Figure 21-6. High-voltage Serial Programming Waveforms
PROGRAM MEMORY
WORD ADDRESS
WITHIN A PAGE
PAGE ADDRESS
WITHIN THE FLASH
INSTRUCTION WORD
PAGE
PCWORD[PAGEMSB:0]:
00
01
02
PAGEEND
PAGE
PCWORDPCPAGE
PCMSB
PAGEMSB
PROGRAM
COUNTER
MSB
MSB
MSB LSB
LSB
LSB
012345678910
SDI
PB0
SII
PB1
SDO
PB2
SCI
PB3

Atmel ATtiny85 Specifications

General

Brand	Atmel
Model	ATtiny85
Category	Microcontrollers
Language	English