Rainbow Electronics ATtiny28L - Manual (Page 46)

46
ATtiny28L/V
1062E–10/01
.
Enter Programming Mode The following algorithm puts the device in parallel programming mode:
1. Apply 4.5 - 5.5V between VCC and GND.
2. Set RESET and BS pins to “0” and wait at least 100 ns.
3. Apply 11.5 - 12.5V to RESET. Any activity on BS within 100 ns after +12V has
been applied to RESET will cause the device to fail entering programming mode.
Table 22. 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)
BS PD4 I
Byte Select (“0” selects low byte, “1” selects
high byte)
XA0 PD5 I XTAL1 Action Bit 0
XA1 PD6 I XTAL1 Action Bit 1
DATA PB7 - PB0 I/O Bi-directional Data Bus (output when OE is low)
Table 23. XA1 and XA0 Coding
XA1 XA0 Action when XTAL1 is Pulsed
0 0
Load Flash/Signature byte Address (High or low address byte for Flash
determined by BS)
0 1 Load Data (High or low data byte for Flash determined by BS)
1 0 Load Command
1 1 No Action, Idle
Table 24. Command Byte Coding
Command Byte Command Executed
1000 0000 Chip Erase
0100 0000 Write Fuse Bits
0010 0000 Write Lock Bits
0001 0000 Write Flash
0000 1000 Read Signature Bytes and Calibration Byte
0000 0100 Read Fuse and Lock Bits
0000 0010 Read Flash