Datasheet

173
8197C–AVR–05/11
ATtiny261A/461A/861A
before issuing the next page. (See Table 18-10.) Accessing the serial programming
interface before the Flash write operation completes can result in incorrect
programming.
5. A: The EEPROM array is programmed one byte at a time by supplying the address and
data together with the appropriate Write instruction. An EEPROM memory location is
first automatically erased before new data is written. If polling (RDY/BSY)
is not used,
the user must wait at least t
WD_EEPROM
before issuing the next byte. (See Table 18-10.)
In a chip erased device, no 0xFFs in the data file(s) need to be programmed.
B: The EEPROM array is programmed one page at a time. The Memory page is loaded
one byte at a time by supplying the 2 LSB of the address and data together with the
Load EEPROM Memory Page instruction. The EEPROM Memory Page is stored by
loading the Write EEPROM Memory Page Instruction with the 6 MSB of the address.
When using EEPROM page access only byte locations loaded with the Load EEPROM
Memory Page instruction is altered. The remaining locations remain unchanged. If poll-
ing (RDY/BSY)
is not used, the used must wait at least t
WD_EEPROM
before issuing the
next page (See Table 18-8). In a chip erased device, no 0xFF in the data file(s) need to
be programmed.
6. Any memory location can be verified by using the Read instruction which returns the
content at the selected address at serial output MISO.
7. At the end of the programming session, RESET
can be set high to commence normal
operation.
8. Power-off sequence (if needed):
Set RESET
to “1”.
Tur n V
CC
power off.
18.6.2 Serial Programming Instruction set
The instruction set is described in Table 18-11 and Figure 18-2 on page 175.
Table 18-10. Minimum Wait Delay Before Writing the Next Flash or EEPROM Location
Symbol Minimum Wait Delay
t
WD_FLASH
4.5 ms
t
WD_EEPROM
4.0 ms
t
WD_ERASE
9.0 ms
t
WD_FUSE
4.5 ms
Table 18-11. Serial Programming Instruction Set
Instruction/Operation
Instruction Format
Byte 1 Byte 2 Byte 3 Byte4
Programming Enable $AC $53 $00 $00
Chip Erase (Program Memory/EEPROM) $AC $80 $00 $00
Poll RDY/BSY
$F0 $00 $00 data byte out
Load Instructions
Load Extended Address byte
(1)
$4D $00 Extended adr $00