atmega32u4-16mu ATMEL Corporation, atmega32u4-16mu Datasheet - Page 386

• Manufacturer Part Number: atmega32u4-16mu
• Description: Atmega32u4 8-bit Avr Microcontroller With 32k Bytes Of Isp Flash And Usb Controller
• Manufacturer: ATMEL Corporation

29.9.4
29.9.5
29.9.6
29.9.7
386
ATmega32U4
PROG_COMMANDS (0x5)
PROG_PAGELOAD (0x6)
PROG_PAGEREAD (0x7)
Data Registers
The AVR specific public JTAG instruction for entering programming commands via the JTAG
port. The 15-bit Programming Command Register is selected as Data Register. The active
states are the following:
The AVR specific public JTAG instruction to directly load the Flash data page via the JTAG port.
An 8-bit Flash Data Byte Register is selected as the Data Register. This is physically the 8 LSBs
of the Programming Command Register. The active states are the following:
The AVR specific public JTAG instruction to directly capture the Flash content via the JTAG port.
An 8-bit Flash Data Byte Register is selected as the Data Register. This is physically the 8 LSBs
of the Programming Command Register. The active states are the following:
The Data Registers are selected by the JTAG instruction registers described in section
gramming Specific JTAG Instructions” on page
programming operations are:
• Capture-DR: The result of the previous command is loaded into the Data Register.
• Shift-DR: The Data Register is shifted by the TCK input, shifting out the result of the previous
• Update-DR: The programming command is applied to the Flash inputs
• Run-Test/Idle: One clock cycle is generated, executing the applied command
• Shift-DR: The Flash Data Byte Register is shifted by the TCK input.
• Update-DR: The content of the Flash Data Byte Register is copied into a temporary register.
• Capture-DR: The content of the selected Flash byte is captured into the Flash Data Byte
• Shift-DR: The Flash Data Byte Register is shifted by the TCK input.
• Reset Register
• Programming Enable Register
• Programming Command Register
• Flash Data Byte Register
command and shifting in the new command.
A write sequence is initiated that within 11 TCK cycles loads the content of the temporary
register into the Flash page buffer. The AVR automatically alternates between writing the low
and the high byte for each new Update-DR state, starting with the low byte for the first
Update-DR encountered after entering the PROG_PAGELOAD command. The Program
Counter is pre-incremented before writing the low byte, except for the first written byte. This
ensures that the first data is written to the address set up by PROG_COMMANDS, and
loading the last location in the page buffer does not make the program counter increment into
the next page.
Register. The AVR automatically alternates between reading the low and the high byte for
each new Capture-DR state, starting with the low byte for the first Capture-DR encountered
after entering the PROG_PAGEREAD command. The Program Counter is post-incremented
after reading each high byte, including the first read byte. This ensures that the first data is
captured from the first address set up by PROG_COMMANDS, and reading the last location
in the page makes the program counter increment into the next page.
384. The Data Registers relevant for
7766A–AVR–03/08
“Pro-