Reading the EEPROM

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ATmega16(L)


	6.	Set OE to “1”.
Reading the EEPROM	The algorithm for reading the EEPROM memory is as follows (refer to “Programming the Flash”
	on page 265 for details on Command and Address loading):
	1.	A: Load Command “0000 0011”.
	2.	G: Load Address High Byte ($00 - $FF)
	3.	B: Load Address Low Byte ($00 - $FF)
	4.	Set			to “0”, and BS1 to “0”. The EEPROM Data byte can now be read at DATA.
			OE
	5.	Set			to “1”.
			OE
Programming the	The algorithm for programming the Fuse Low bits is as follows (refer to “Programming the Flash”
Fuse Low Bits	on page 265 for details on Command and Data loading):
	1.	A: Load Command “0100 0000”.
	2.	C: Load Data Low Byte. Bit n = “0” programs and bit n = “1” erases the Fuse bit.
	3.	Set BS1 to “0” and BS2 to “0”.
	4.	Give					to go high.
				WR		a negative pulse and wait for RDY/BSY
Programming the	The algorithm for programming the Fuse high bits is as follows (refer to “Programming the Flash”
Fuse High Bits	on page 265 for details on Command and Data loading):
	1.	A: Load Command “0100 0000”.
	2.	C: Load Data Low Byte. Bit n = “0” programs and bit n = “1” erases the Fuse bit.
	3.	Set BS1 to “1” and BS2 to “0”. This selects high data byte.
	4.	Give					to go high.
				WR		a negative pulse and wait for RDY/BSY
	5.	Set BS1 to “0”. This selects low data byte.

Figure 131. Programming the Fuses

			Write Fuse Low byte			Write Fuse high byte
	A	C		A	C
DATA	$40	DATA	XX	$40	DATA	XX
DATA

XA1

XA0

BS1

BS2

XTAL1

RDY/BSY

RESET +12V

PAGEL

269

2466P–AVR–08/07

Programming the Lock The algorithm for programming the Lock bits is as follows (refer to “Programming the Flash” on Bits page 265 for details on Command and Data loading):

1.A: Load Command “0010 0000”.

2.C: Load Data Low Byte. Bit n = “0” programs the Lock bit.

3.Give WR a negative pulse and wait for RDY/BSY to go high.

The Lock bits can only be cleared by executing Chip Erase.

Reading the Fuse and The algorithm for reading the Fuse and Lock bits is as follows (refer to “Programming the Flash” Lock Bits on page 265 for details on Command loading):

1.A: Load Command “0000 0100”.

2.Set OE to “0”, BS2 to “0” and BS1 to “0”. The status of the Fuse Low bits can now be read at DATA (“0” means programmed).

3.Set OE to “0”, BS2 to “1” and BS1 to “1”. The status of the Fuse High bits can now be read at DATA (“0” means programmed).

4.Set OE to “0”, BS2 to “0” and BS1 to “1”. The status of the Lock bits can now be read at DATA (“0” means programmed).

5.Set OE to “1”.

Figure 132. Mapping between BS1, BS2 and the Fuseand Lock Bits during Read

Fuse Low Byte

DATA

Lock Bits

BS1

Fuse High Byte

Reading the Signature

BS2

The algorithm for reading the Signature bytes is as follows (refer to “Programming the Flash” on

Bytes

page 265 for details on Command and Address loading):

A: Load Command “0000 1000”.

B: Load Address Low Byte ($00 - $02).

Set

to “0”, and BS1 to “0”. The selected Signature byte can now be read at DATA.

Set

to “1”.

Reading the

The algorithm for reading the Calibration byte is as follows (refer to “Programming the Flash” on

Calibration Byte

page 265 for details on Command and Address loading):

A: Load Command “0000 1000”.

B: Load Address Low Byte, $00.

Set

to “0”, and BS1 to “1”. The Calibration byte can now be read at DATA.

Set

to “1”.

270 ATmega16(L)

2466P–AVR–08/07

ATmega16(L)

Parallel Programming Figure 133. Parallel Programming Timing, Including some General Timing Requirements

Characteristics

tXLWL

XTAL1

tXHXL

Data & Contol

tDVXH

tXLDX

(DATA, XA0/1, BS1, BS2)

tBVPH

tPLBX

t BVWL

tWLBX

PAGEL

tPHPL

tWL WH

tPLWL

WLRL

RDY/BSY

tWLRH

Figure 134. Parallel Programming Timing, Loading Sequence with Timing Requirements(1)

LOAD ADDRESS

LOAD DATA

LOAD DATA LOAD DATA

LOAD ADDRESS

(LOW BYTE)

(HIGH BYTE)

(LOW BYTE)

t XLXH

tXLPH

tPLXH

XTAL1

BS1

PAGEL

DATA

ADDR0 (Low Byte)

DATA (Low Byte)

DATA (High Byte)

ADDR1 (Low Byte)

XA0

XA1

Note: 1.

The timing requirements shown in Figure 133 (i.e., tDVXH, tXHXL, and tXLDX) also apply to load-

ing operation.

271

2466P–AVR–08/07

Figure 135. Parallel Programming Timing, Reading Sequence (within the Same Page) with

Timing Requirements(1)

LOAD ADDRESS

READ DATA

LOAD ADDRESS

(LOW BYTE)

(HIGH BYTE)

(LOW BYTE)

tXLOL

XTAL1

BS1

tBVDV

tOLDV

tOHDZ

ADDR1 (Low Byte)

DATA

ADDR0 (Low Byte)

DATA (Low Byte)

DATA (High Byte)

XA0

XA1

Note: 1.

The timing requirements shown in Figure 133 (i.e., tDVXH, tXHXL, and tXLDX) also apply to read-

ing operation.

Table 113.

Parallel Programming Characteristics, VCC = 5 V ± 10%

Symbol

Parameter

Min

Typ

Max

Units

VPP

Programming Enable Voltage

11.5

12.5

IPP

Programming Enable Current

250

μA

tDVXH

Data and Control Valid before XTAL1 High

tXLXH

XTAL1 Low to XTAL1 High

200

tXHXL

XTAL1 Pulse Width High

150

tXLDX

Data and Control Hold after XTAL1 Low

tXLWL

XTAL1 Low to

Low

tXLPH

XTAL1 Low to PAGEL high

tPLXH

PAGEL low to XTAL1 high

150

tBVPH

BS1 Valid before PAGEL High

tPHPL

PAGEL Pulse Width High

150

tPLBX

BS1 Hold after PAGEL Low

tWLBX

BS2/1 Hold after

Low

tPLWL

PAGEL Low to

Low

tBVWL

BS1 Valid to

Low

tWLWH

Pulse Width Low

150

tWLRL

Low

μs

Low to RDY/BSY

tWLRH

High(1)

3.7

4.5

Low to RDY/BSY

tWLRH_CE

High for Chip Erase(2)

7.5

Low to RDY/BSY

tXLOL

XTAL1 Low to

Low

272 ATmega16(L)

2466P–AVR–08/07

Serial

Downloading

SPI Serial

Programming Pin

Mapping

ATmega16(L)

Table 113. Parallel Programming Characteristics, VCC = 5 V ± 10% (Continued)

Symbol	Parameter		Min	Typ Max	Units
tBVDV	BS1 Valid to DATA valid		0	250	ns
tOLDV		Low to DATA Valid		250	ns
	OE
tOHDZ		High to DATA Tri-stated		250	ns
	OE

Notes: 1. tWLRH is valid for the Write Flash, Write EEPROM, Write Fuse bits and Write Lock bits commands.

2.tWLRH_CE is valid for the Chip Erase command.

Both the Flash and EEPROM memory arrays can be programmed using the serial SPI bus while RESET is pulled to GND. The serial interface consists of pins SCK, MOSI (input), and MISO

(output). After RESET is set low, the Programming Enable instruction needs to be executed first before program/erase operations can be executed. NOTE, in Table 114 on page 273, the pin mapping for SPI programming is listed. Not all parts use the SPI pins dedicated for the internal SPI interface.

Table 114. Pin Mapping SPI Serial Programming

Symbol	Pins	I/O	Description

MOSI	PB5	I	Serial Data in

MISO	PB6	O	Serial Data out

SCK	PB7	I	Serial Clock

Figure 136. SPI Serial Programming and Verify(1)

			+2.7 - 5.5V
			+2.7 - 5.5V
		VCC
			+2.7 - 5.5V(2)
MOSI		PB5
MOSI		PB5
MISO		AVCC
		PB6
		PB6
	SCK	PB7
	SCK	PB7
		XTAL1
		XTAL1

RESET

GND

Notes: 1. If the device is clocked by the Internal Oscillator, it is no need to connect a clock source to the XTAL1 pin.

2. VCC -0.3V < AVCC < VCC +0.3V, however, AVCC should always be within 2.7 - 5.5V

When programming the EEPROM, an auto-erase cycle is built into the self-timed programming operation (in the serial mode ONLY) and there is no need to first execute the Chip Erase instruc-

273

2466P–AVR–08/07

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