Rainbow-electronics Atmega169L Manual de usuario descargar pdf (Pagina 292)

292

ATmega169V/L

2514A–AVR–08/02

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.

Figure 134. Flash Data Byte Register

The state machine controlling the Flash Data Byte Register is clocked by TCK. During

normal operation in which eight bits are shifted for each Flash byte, the clock cycles

needed to navigate through the TAP controller automatically feeds the state machine for

the Flash Data Byte Register with sufficient number of clock pulses to complete its oper-

ation transparently for the user. However, if too few bits are shifted between each

Update-DR state during page load, the TAP controller should stay in the Run-Test/Idle

state for some TCK cycles to ensure that there are at least 11 TCK cycles between each

Update-DR state.

Programming Algorithm All references below of type “1a”, “1b”, and so on, refer to Table 132.

Entering Programming Mode 1. Enter JTAG instruction AVR_RESET and shift 1 in the Reset Register.

2. Enter instruction PROG_ENABLE and shift 0b1010_0011_0111_0000 in the Pro-

gramming Enable Register.

Leaving Programming Mode 1. Enter JTAG instruction PROG_COMMANDS.

2. Disable all programming instructions by using no operation instruction 11a.

3. Enter instruction PROG_ENABLE and shift 0b0000_0000_0000_0000 in the

programming Enable Register.

4. Enter JTAG instruction AVR_RESET and shift 0 in the Reset Register.

Performing Chip Erase 1. Enter JTAG instruction PROG_COMMANDS.

2. Start Chip Erase using programming instruction 1a.

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

WLRH_CE

(refer to Table 128 on page 278).

TDI

TDO

Flash

EEPROM

Fuses

Lock Bits

STROBES

ADDRESS

State

Machine

1 2 ... 287 288 289 290 291 292 293 294 295 296 297 ... 316 317

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Rainbow-electronics Atmega169L Manual de usuario Pagina 292