Datasheet

358
ATmega16U4/32U4 [DATASHEET]
Atmel-7766J-USB-ATmega16U4/32U4-Datasheet_04/2016
Table 28-7. BS2 and BS1 Encoding
BS2 BS1
Flash / EEPROM
Address
Flash Data
Loading /
Reading
Fuse
Programming
Reading Fuse
and Lock Bits
0 0 Low Byte Low Byte Low Byte Fuse Low Byte
0 1 High Byte High Byte High Byte Lock bits
1 0
Extended High
Byte
Reserved Extended Byte
Extended Fuse
Byte
1 1 Reserved Reserved Reserved Fuse High Byte
Table 28-8. 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
Table 28-9. XA1 and XA0 Enoding
XA1 XA0 Action when XTAL1 is Pulsed
0 0
Load Flash or EEPROM Address (High or low address byte determined by
BS2 and BS1)
0 1 Load Data (High or Low data byte for Flash determined by BS1)
1 0 Load Command
1 1 No Action, Idle
Table 28-10. Command Byte Bit Encoding
Command Byte Command Executed
1000 0000 Chip Erase
0100 0000 Write Fuse bits
0010 0000 Write Lock bits
0001 0000 Write Flash
0001 0001 Write EEPROM
0000 1000 Read Signature Bytes and Calibration byte
0000 0100 Read Fuse and Lock bits
0000 0010 Read Flash
0000 0011 Read EEPROM