ATmega16U4 datasheet(377/408 Pages) ATMEL

377 / 408 page

377

7766D–AVR–01/09

ATmega16U4/ATmega32U4

28.9.15

Performing Chip Erase

Enter JTAG instruction PROG_COMMANDS.

Start Chip Erase using programming instruction 1a.

Poll for Chip Erase complete using programming instruction 1b, or wait for t

WLRH_CE

(refer to Table 28-13 on page 362).

28.9.16

Programming the Flash

Before programming the Flash a Chip Erase must be performed, see “Performing Chip Erase”

on page 377.

Enter JTAG instruction PROG_COMMANDS.

Enable Flash write using programming instruction 2a.

Load address Extended High byte using programming instruction 2b.

Load address High byte using programming instruction 2c.

Load address Low byte using programming instruction 2d.

Load data using programming instructions 2e, 2f and 2g.

Repeat steps 5 and 6 for all instruction words in the page.

Write the page using programming instruction 2h.

Poll for Flash write complete using programming instruction 2i, or wait for t

WLRH (refer to

Table 28-13 on page 362).

10. Repeat steps 3 to 9 until all data have been programmed.

A more efficient data transfer can be achieved using the PROG_PAGELOAD instruction:

Enter JTAG instruction PROG_COMMANDS.

Enable Flash write using programming instruction 2a.

Load the page address using programming instructions 2b, 2c and 2d. PCWORD (refer

to Table 28-11 on page 353) is used to address within one page and must be written as

Enter JTAG instruction PROG_PAGELOAD.

Load the entire page by shifting in all instruction words in the page byte-by-byte, start-

ing with the LSB of the first instruction in the page and ending with the MSB of the last

instruction in the page. Use Update-DR to copy the contents of the Flash Data Byte

before each new word.

Enter JTAG instruction PROG_COMMANDS.

Write the page using programming instruction 2h.

Poll for Flash write complete using programming instruction 2i, or wait for t

WLRH (refer to

Table 28-13 on page 362).

Repeat steps 3 to 8 until all data have been programmed.

28.9.17

Reading the Flash

Enter JTAG instruction PROG_COMMANDS.

Enable Flash read using programming instruction 3a.

Load address using programming instructions 3b, 3c and 3d.

Read data using programming instruction 3e.

Repeat steps 3 and 4 until all data have been read.

A more efficient data transfer can be achieved using the PROG_PAGEREAD instruction:

ATmega16U4 Datasheet(PDF) 377 Page - ATMEL Corporation

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