Datasheet

291
7810C–AVR–10/12
Atmel ATmega328P [Preliminary]
Table 27-11. 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
PAG EL PD 7 I
Program memory and EEPROM Data Page
Load
BS2 PC2 I
Byte Select 2 (“0” selects Low byte, “1” selects
2’nd High byte)
DATA {PC[1:0]: PB[5:0]} I/O Bi-directional Data bus (Output when OE is low)
Table 27-12. 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
Table 27-13. 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