Datasheet

Symbol Parameter Min Typ Max Units

WLRH_CE

WR Low to RDY/BSY High for Chip Erase

(2)

7.5 9 ms

XLOL

XTAL1 Low to OE Low 0 ns

BVDV

BS1 Valid to DATA valid 0 250 ns

OLDV

OE Low to DATA Valid 250 ns

OHDZ

OE High to DATA Tri-stated 250 ns

Note:

1. t

WLRH

is valid for the Write Flash, Write EEPROM, Write Fuse Bits and Write Lock Bits commands.

2. t

WLRH_CE

is valid for the Chip Erase command.

29.8 Serial Downloading

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 (output). After

RESET is set low, the Programming Enable instruction needs to be executed first before program/erase

operations can be executed.

Note: The pin mapping for SPI programming is listed in the following section. Not all parts use the SPI

pins dedicated for the internal SPI interface.

29.9 Serial Programming Pin Mapping

Table 29-13. Pin Mapping Serial Programming

Symbol Pins I/O Description

MOSI PB5 I Serial Data in

MISO PB6 O Serial Data out

SCK PB7 I Serial Clock

AVR 8-Bit Microcontroller

MEMPROG- Memory Programming

Datasheet Complete

40001974A-page 302