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ATmega16(L)

Table 106. Fuse Low Byte

Fuse Low

Bit

 

 

 

Byte

No.

Description

Default Value

 

 

 

 

 

BODLEVEL

7

Brown-out Detector trigger level

1

(unprogrammed)

 

 

 

 

 

BODEN

6

Brown-out Detector enable

1

(unprogrammed, BOD disabled)

 

 

 

 

 

SUT1

5

Select start-up time

1

(unprogrammed)(1)

SUT0

4

Select start-up time

0

(programmed)(1)

CKSEL3

3

Select Clock source

0

(programmed)(2)

CKSEL2

2

Select Clock source

0

(programmed)(2)

CKSEL1

1

Select Clock source

0

(programmed)(2)

CKSEL0

0

Select Clock source

1

(unprogrammed)(2)

Notes: 1. The default value of SUT1..0 results in maximum start-up time. SeeTable 10 on page 29 for details.

2.The default setting of CKSEL3..0 results in internal RC Oscillator @ 1MHz. See Table 2 on page 25 for details.

The status of the Fuse bits is not affected by Chip Erase. Note that the Fuse bits are locked if Lock bit1 (LB1) is programmed. Program the Fuse bits before programming the Lock bits.

Latching of Fuses The Fuse values are latched when the device enters programming mode and changes of the Fuse values will have no effect until the part leaves Programming mode. This does not apply to the EESAVE Fuse which will take effect once it is programmed. The fuses are also latched on Power-up in Normal mode.

Signature Bytes

Calibration Byte

All Atmel microcontrollers have a three-byte signature code which identifies the device. This code can be read in both serial and parallel mode, also when the device is locked. The three bytes reside in a separate address space.

For the ATmega16 the signature bytes are:

1.$000: $1E (indicates manufactured by Atmel)

2.$001: $94 (indicates 16KB Flash memory)

3.$002: $03 (indicates ATmega16 device when $001 is $94)

The ATmega16 stores four different calibration values for the internal RC Oscillator. These bytes resides in the signature row High Byte of the addresses 0x0000, 0x0001, 0x0002, and 0x0003 for 1, 2, 4, and 8 Mhz respectively. During Reset, the 1 MHz value is automatically loaded into the OSCCAL Register. If other frequencies are used, the calibration value has to be loaded manually, see “Oscillator Calibration Register – OSCCAL” on page 30 for details.

261

2466P–AVR–08/07

Page Size

Parallel

Programming

Parameters, Pin

Mapping, and

Commands

Signal Names

Table 107. No. of Words in a Page and no. of Pages in the Flash

Flash Size

Page Size

PCWORD

No. of Pages

PCPAGE

PCMSB

 

 

 

 

 

 

8K words (16K bytes)

64 words

PC[5:0]

128

PC[12:6]

12

 

 

 

 

 

 

Table 108. No. of Words in a Page and no. of Pages in the EEPROM

EEPROM Size

Page Size

PCWORD

No. of Pages

PCPAGE

EEAMSB

 

 

 

 

 

 

512 bytes

4 bytes

EEA[1:0]

128

EEA[8:2]

8

 

 

 

 

 

 

This section describes how to parallel program and verify Flash Program memory, EEPROM Data memory, Memory Lock bits, and Fuse bits in the ATmega16. Pulses are assumed to be at least 250 ns unless otherwise noted.

In this section, some pins of the ATmega16 are referenced by signal names describing their functionality during parallel programming, see Figure 127 and Table 109. Pins not described in the following table are referenced by pin names.

The XA1/XA0 pins determine the action executed when the XTAL1 pin is given a positive pulse. The bit coding is shown in Table 111.

When pulsing WR or OE, the command loaded determines the action executed. The different Commands are shown in Table 112.

Figure 127. Parallel Programming

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

+5V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PD1

 

 

 

 

 

 

 

 

 

 

 

RDY/BSY

 

 

VCC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

+5V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

OE

PD2

 

 

 

 

 

 

 

 

 

 

 

 

 

WR

 

 

 

 

 

 

 

 

 

 

 

PD3

AVCC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BS1

 

 

 

 

PD4

PB7 - PB0

 

 

 

DATA

 

 

 

 

 

 

 

 

XA0

 

 

 

 

 

 

 

 

 

 

 

PD5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

XA1

 

 

 

 

PD6

 

 

 

 

 

 

 

 

 

 

 

 

 

PAGEL

 

 

 

PD7

 

 

 

 

 

 

 

 

 

 

 

 

 

+12 V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RESET

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BS2

 

PA0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

XTAL1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

GND

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

262 ATmega16(L)

2466P–AVR–08/07

ATmega16(L)

Table 109. Pin Name Mapping

 

Signal Name in

 

 

 

 

 

 

Programming Mode

Pin Name

I/O

Function

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0: Device is busy programming, 1: Device is ready

 

RDY/BSY

PD1

O

 

for new command

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PD2

I

Output Enable (Active low)

 

OE

 

 

 

 

 

 

 

 

 

 

PD3

I

Write Pulse (Active low)

 

WR

 

 

 

 

 

 

 

 

 

 

BS1

PD4

I

Byte Select 1 (“0” selects Low byte, “1” selects

 

High byte)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

XA0

PD5

I

XTAL Action Bit 0

 

 

 

 

 

 

XA1

PD6

I

XTAL Action Bit 1

 

 

 

 

 

 

PAGEL

PD7

I

Program Memory and EEPROM data Page Load

 

 

 

 

 

 

 

 

 

 

BS2

PA0

I

Byte Select 2 (“0” selects Low byte, “1” selects

 

2’nd High byte)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DATA

PB7-0

I/O

Bidirectional Data bus (Output when

 

is low)

 

OE

 

 

 

 

 

 

 

 

 

 

 

Table 110. Pin Values used to Enter Programming Mode

Pin

Symbol

Value

 

 

 

PAGEL

Prog_enable[3]

0

 

 

 

XA1

Prog_enable[2]

0

 

 

 

XA0

Prog_enable[1]

0

 

 

 

BS1

Prog_enable[0]

0

 

 

 

Table 111. XA1 and XA0 Coding

XA1

XA0

Action when XTAL1 is Pulsed

 

 

 

0

0

Load Flash or EEPROM Address (High or low address byte determined by BS1)

 

 

 

0

1

Load Data (High or Low data byte for Flash determined by BS1)

 

 

 

1

0

Load Command

 

 

 

1

1

No Action, Idle

 

 

 

Table 112. Command Byte Bit Coding

Command Byte

Command Executed

 

 

1000 0000

Chip Erase

 

 

0100 0000

Write Fuse Bits

 

 

0010 0000

Write Lock Bits

 

 

0001 0000

Write Flash

 

 

0001 0001

Write EEPROM

 

 

263

2466P–AVR–08/07

Table 112. Command Byte Bit Coding

Command Byte

Command Executed

 

 

0000 1000

Read Signature Bytes and Calibration byte

 

 

0000 0100

Read Fuse and Lock bits

 

 

0000 0010

Read Flash

 

 

0000 0011

Read EEPROM

 

 

264 ATmega16(L)

2466P–AVR–08/07

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