285
ATmega165A/PA/325A/PA/3250A/PA/645A/P/6450A/P [DATASHEET]
8285E–AVR–02/2013
27.9.16
Programming the Flash
1.
Enter JTAG instruction PROG_COMMANDS.
2.
Enable Flash write using programming instruction 2a.
3.
Load address High byte using programming instruction 2b.
4.
Load address Low byte using programming instruction 2c.
5.
Load data using programming instructions 2d, 2e and 2f.
6.
Repeat steps 4 and 5 for all instruction words in the page.
7.
Write the page using programming instruction 2g.
8.
Poll for Flash write complete using programming instruction 2h, or wait for t
9.
Repeat steps 3 to 7 until all data have been programmed.
A more efficient data transfer can be achieved using the PROG_PAGELOAD instruction:
1.
Enter JTAG instruction PROG_COMMANDS.
2.
Enable Flash write using programming instruction 2a.
3.
Load the page address using programming instructions 2b and 2c. PCWORD (refer to
Table 27-7 on page260) is used to address within one page and must be written as 0.
4.
Enter JTAG instruction PROG_PAGELOAD.
5.
Load the entire page by shifting in all instruction words in the page byte-by-byte, starting 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 Register into the Flash page location and to auto-increment the
Program Counter before each new word.
6.
Enter JTAG instruction PROG_COMMANDS.
7.
Write the page using programming instruction 2g.
8.
Poll for Flash write complete using programming instruction 2h, or wait for t
9.
Repeat steps 3 to 8 until all data have been programmed.
27.9.17
Reading the Flash
1.
Enter JTAG instruction PROG_COMMANDS.
2.
Enable Flash read using programming instruction 3a.
3.
Load address using programming instructions 3b and 3c.
4.
Read data using programming instruction 3d.
5.
Repeat steps 3 and 4 until all data have been read.
A more efficient data transfer can be achieved using the PROG_PAGEREAD instruction:
1.
Enter JTAG instruction PROG_COMMANDS.
2.
Enable Flash read using programming instruction 3a.
3.
Load the page address using programming instructions 3b and 3c. PCWORD (refer to
Table 27-7 on page260) is used to address within one page and must be written as 0.
4.
Enter JTAG instruction PROG_PAGEREAD.
5.
Read the entire page (or Flash) by shifting out all instruction words in the page (or Flash), starting with the
LSB of the first instruction in the page (Flash) and ending with the MSB of the last instruction in the page
(Flash). The Capture-DR state both captures the data from the Flash, and also auto-increments the pro-