While the lower bits in the address are mapped to words within the page, the higher bits
address the pages within the FLASH. This is illustrated in Figure 105 on page 226. Note
that if less than eight bits are required to address words in the page (pagesize < 256),
the most significant bit(s) in the address Low byte are used to address the page when
performing a page write.
G. Load Address High byte
1. Set XA1, XA0 to “00”. This enables address loading.
2. Set BS1 to “1”. This selects high address.
3. Set DATA = Address High byte (0x00 - 0xFF).
4. Give XTAL1 a positive pulse. This loads the address High byte.
H. Program Page
1. Set BS1 = “0”
2. Give WR a negative pulse. This starts programming of the entire page of data.
RDY/BSY goes low.
3. Wait until RDY/BSY goes high. (See Figure 106 for signal waveforms)
I. Repeat B through H until the entire Flash is programmed or until all data has been
programmed.
J. End Page Programming
1. Set XA1, XA0 to “10”. This enables command loading.
2. Set DATA to “0000 0000”. This is the command for No Operation.
3. Give XTAL1 a positive pulse. This loads the command, and the internal write sig-
nals are reset.
Figure 105. Addressing the Flash which is Organized in Pages(1)
PCMSB
PAGEMSB
PCWORD
PROGRAM
COUNTER
PCPAGE
PAGE ADDRESS
WITHIN THE FLASH
WORD ADDRESS
WITHIN A PAGE
PROGRAM MEMORY
PAGE
PAGE
INSTRUCTION WORD
PCWORD[PAGEMSB:0]:
00
01
02
PAGEEND
Note:
1. PCPAGE and PCWORD are listed in Table 93 on page 224.
226
ATmega8(L)
2486M–AVR–12/03
ATMEL [ ATMEL ]
