
185
8246B–AVR–09/11
ATtiny2313A/4313
Signals are described in
Table 21-3, below. Pins not listed in the table are referenced by pin
names.
Pulses are assumed to be at least 250 ns, unless otherwise noted.
Pins XA1 and XA0 determine the action when CLKI is given a positive pulse, as shown in
TableTable 21-3.
Pin and Signal Names Used in Programming Mode
Signal Name
Pin(s)
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/PAGEL
PD4
I
Byte Select 1 (“0” selects low byte, “1” selects high byte).
Program Memory and EEPROM Data Page Load.
XA0
PD5
I
XTAL Action Bit 0
XA1/BS2
PD6
I
XTAL Action Bit 1.
Byte Select 2 (0: low byte, 1: 2nd high byte).
DATA I/O
PB7-0
I/O
Bi-directional Data bus (Output when OE is low).
Table 21-4.
Pin Values Used to Enter Programming Mode
Pin
Symbol
Value
XA1
Prog_enable[3]
0
XA0
Prog_enable[2]
0
BS1
Prog_enable[1]
0
WR
Prog_enable[0]
0
Table 21-5.
XA1 and XA0 Coding
XA1
XA0
Action when CLKI is Pulsed
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
No action, idle