ATMEGA8L ATMEL [ATMEL Corporation], ATMEGA8L Datasheet - Page 232

• Manufacturer Part Number: ATMEGA8L
• Description: 8-bit AVR with 8K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

Serial Downloading
Serial Programming Pin
Mapping
232
ATmega8(L)
Table 95. Parallel Programming Characteristics, V
Notes:
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 96 on page 232, the pin mapping for SPI programming is listed. Not all parts use
the SPI pins dedicated for the internal SPI interface.
Table 96. Pin Mapping Serial Programming
Figure 112. Serial Programming and Verify
Notes:
When programming the EEPROM, an auto-erase cycle is built into the self-timed pro-
gramming 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.
Depending on CKSEL Fuses, a valid clock must be present. The minimum low and high
periods for the Serial Clock (SCK) input are defined as follows:
Symbol
t
t
t
BVDV
OLDV
OHDZ
Symbol
1.
2. t
1. If the device is clocked by the Internal Oscillator, it is no need to connect a clock
2. V
MOSI
MISO
SCK
Bits commands.
source to the XTAL1 pin.
t
WLRH_CE
WLRH
CC
Parameter
BS1 Valid to DATA valid
OE Low to DATA Valid
OE High to DATA Tri-stated
- 0.3 < AVCC < V
is valid for the Write Flash, Write EEPROM, Write Fuse Bits and Write Lock
is valid for the Chip Erase command.
MOSI
MISO
SCK
Pins
PB3
PB4
PB5
CC
+ 0.3, however, AVCC should always be within 2.7 - 5.5V.
PB3
PB4
PB5
XTAL1
RESET
GND
I/O
(1)
O
I
I
AVCC
VCC
CC
+2.7 - 5.5V
Description
Serial data in
Serial data out
Serial clock
+2.7 - 5.5V
= 5V ± 10% (Continued)
Min
(2)
0
Typ
Max
250
250
250
2486M–AVR–12/03
Units
ns
ns
ns