Datasheet

162
8183F–AVR–06/12
ATtiny24A/44A/84A
19.5 Serial Programming
Both the Flash and EEPROM memory arrays can be programmed using the serial SPI bus while
RESET
is pulled to GND. The serial interface consists of pins SCK, MOSI (input) and MISO (out-
put). See Figure 19-1 below.
Figure 19-1. Serial Programming and Verify
Note: If clocked by internal oscillator there is no need to connect a clock source to the CLKI pin.
After RESET is set low, the Programming Enable instruction needs to be executed first before
program/erase operations can be executed.
Note: In Table 19-10 above, the pin mapping for SPI programming is listed. Not all devices use the SPI
pins dedicated for the internal SPI interface.
When programming the EEPROM, an auto-erase cycle is built into the self-timed programming
operation (in the Serial mode ONLY) and there is no need to first execute the Chip Erase
instruction. The Chip Erase operation turns the content of every memory location in both the
Program and EEPROM arrays into 0xFF.
Table 19-10. Pin Mapping Serial Programming
Symbol Pins I/O Description
MOSI PA6 I Serial Data in
MISO PA5 O Serial Data out
SCK PA4 I Serial Clock
VCC
GND
SCK
MISO
MOSI
RESET
+1.8 - 5.5V