285
4317I–AVR–01/08
AT90PWM2/3/2B/3B
25.7
Serial Programming Pin Mapping
Table 25-9.
XA1 and XA0 Coding
XA1
XA0
Action when XTAL1 is Pulsed
0
0
Load Flash or EEPROM Address (High or low address byte determined by
BS1).
0
1
Load Data (High or Low data byte for Flash determined by BS1).
1
0
Load Command
1
1
No Action, Idle
Table 25-10. Command Byte Bit Coding
Command Byte
Command Executed
1000 0000
Chip Erase
0100 0000
Write Fuse bits
0010 0000
Write Lock bits
0001 0000
Write Flash
0001 0001
Write EEPROM
0000 1000
Read Signature Bytes and Calibration byte
0000 0100
Read Fuse and Lock bits
0000 0010
Read Flash
0000 0011
Read EEPROM
Table 25-11. No. of Words in a Page and No. of Pages in the Flash
Device
Flash Size
Page Size
PCWORD
No. of
Pages
PCPAGE
PCMSB
AT90PWM2/2B/3/
3B
4K words
(8K bytes)
32 words
PC[4:0]
128
PC[11:5]
11
Table 25-12. No. of Words in a Page and No. of Pages in the EEPROM
Device
EEPROM
Size
Page
Size
PCWORD
No. of
Pages
PCPAGE
EEAMSB
AT90PWM2/2B/3/
3B
512 bytes
4 bytes
EEA[1:0]
128
EEA[8:2]
8
Table 25-13. Pin Mapping Serial Programming
Symbol
Pins
I/O
Description
MOSI_A
PD3
I
Serial Data in
MISO_A
PD2
O
Serial Data out
SCK_A
PD4
I
Serial Clock