284
4317I–AVR–01/08
AT90PWM2/3/2B/3B
Figure 25-1. Parallel Programming
Table 25-7.
Pin Name Mapping
Signal Name in
Programming Mode
Pin Name
I/O
Function
RDY/BSY
PD1
O
0: Device is busy programming, 1: Device is
ready for new command
OE
PD2
I
Output Enable (Active low)
WR
PD3
I
Write Pulse (Active low)
BS1
PD4
I
Byte Select 1 (“0” selects Low byte, “1” selects
High byte)
XA0
PD5
I
XTAL Action Bit 0
XA1
PD6
I
XTAL Action Bit 1
PAGEL
PD7
I
Program memory and EEPROM Data Page
Load
BS2
PE2
I
Byte Select 2 (“0” selects Low byte, “1” selects
2’nd High byte)
DATA
PB[7:0]
I/O
Bi-directional Data bus (Output when OE is
low)
Table 25-8.
Pin Values Used to Enter Programming Mode
Pin
Symbol
Value
PAGEL
Prog_enable[3]
0
XA1
Prog_enable[2]
0
XA0
Prog_enable[1]
0
BS1
Prog_enable[0]
0
VCC
GND
XTAL1
XA0
RDY/BSY
OE
RESET
+ 5V
AVCC
+ 5V
PD1
+ 12 V
PD7
PD6
PD5
PD4
PD3
PD2
PE2
WR
XA1
BS2
PAGEL
BS1
DATA
PB[7:0]