Datasheet

Table Of Contents
261
ATmega32A [DATASHEET]
Atmel-8155D-AVR-ATmega32A-Datasheet_02/2014
Notes: 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.
27.8 SPI 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, in Table 26-12 on page 280, the pin mapping for SPI programming is listed. Not all parts use the SPI pins
dedicated for the internal SPI interface.
27.9 SPI Serial Programming Pin Mapping
t
PHPL
PAGEL Pulse Width High 150 ns
t
PLBX
BS1 Hold after PAGEL Low 67 ns
t
WLBX
BS2/1 Hold after WR Low 67 ns
t
PLWL
PAGEL Low to WR Low 67 ns
t
BVWL
BS1 Valid to WR Low 67 ns
t
WLWH
WR Pulse Width Low 150 ns
t
WLRL
WR Low to RDY/BSY Low 0 1 s
t
WLRH
WR Low to RDY/BSY High
(1)
3.7 4.5 ms
t
WLRH_CE
WR Low to RDY/BSY High for Chip Erase
(2)
7.5 9 ms
t
XLOL
XTAL1 Low to OE Low 0 ns
t
BVDV
BS1 Valid to DATA valid 0 250 ns
t
OLDV
OE Low to DATA Valid 250 ns
t
OHDZ
OE High to DATA Tri-stated 250 ns
Table 27-11. Parallel Programming Characteristics, V
CC
= 5V ±10% (Continued)
Symbol Parameter Min Typ Max Units
Table 27-12. Pin Mapping SPI Serial Programming
Symbol Pins I/O Description
MOSI PB5 I Serial Data in
MISO PB6 O Serial Data out
SCK PB7 I Serial Clock