Datasheet

314
ATmega169A/PA/329A/PA/649A/P/3290A/PA/6490A/P [DATASHEET]
8284E–AVR–02/2013
• 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 command and
shifting in the new command
• Update-DR: The programming command is applied to the Flash inputs
• Run-Test/Idle: One clock cycle is generated, executing the applied command (not always required, see Table 28-
17 on page 317)
28.9.5 PROG_PAGELOAD (0x6)
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 eight LSBs of the Programming Com-
mand Register. The active states are the following:
• 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. 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
28.9.6 PROG_PAGEREAD (0x7)
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 eight LSBs of the Programming Com-
mand Register. The active states are the following:
• Capture-DR: The content of the selected Flash byte is captured into the Flash Data Byte 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
• Shift-DR: The Flash Data Byte Register is shifted by the TCK input