Datasheet

257
7734Q–AVR–02/12
AT90PWM81/161
Figure 21-2. Addressing the flash, which is organized in pages
(1)
.
Note: 1. PCPAGE and PCWORD are listed in Table 21-12 on page 254.
Figure 21-3. Programming the flash waveforms
(1)
.
Note: 1. “XX” is don’t care. The letters refer to the programming description above.
21.7.5 Programming the EEPROM
The EEPROM is organized in pages, see Table 21-13 on page 254. When programming the
EEPROM, the program data is latched into a page buffer. This allows one page of data to be
programmed simultaneously. The programming algorithm for the EEPROM data memory is as
follows (refer to “Programming the Flash” on page 255 for details on Command, Address and
Data loading):
1. A: Load Command “0001 0001”.
2. G: Load Address High Byte (0x00 - 0xFF).
3. B: Load Address Low Byte (0x00 - 0xFF).
4. C: Load Data (0x00 - 0xFF).
5. E: Latch data (give PAGEL a positive pulse).
K: Repeat 3 through 5 until the entire buffer is filled
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
RDY/BSY
WR
OE
RESET +12V
0x10 ADDR. LOW
ADDR. HIGH
DATA
DATA L OW D ATA HIGH
ADDR. LOW DATA L OW DATA HIGH
XA1/BS2
XA0
PAGEL/BS1
XTAL1
XX XX
XX
ABCDEBC DEGH
F