Datasheet

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 Table
21-5.
Table 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: 2
nd
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 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