ATtiny48 datasheet(196/266 Pages) ATMEL

196 / 266 page

196

8008C–AVR–03/09

ATtiny48/88

Figure 20-6. Mapping Between BS1, BS2 and the Fuse and Lock Bits During Read

20.7.13

Reading the Signature Bytes

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

page 190 for details on Command and Address loading):

A: Load Command “0000 1000”.

B: Load Address Low Byte (0x00 – 0x02).

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

Set OE to “1”.

20.7.14

Reading the Calibration Byte

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

page 190 for details on Command and Address loading):

A: Load Command “0000 1000”.

B: Load Address Low Byte, 0x00.

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

Set OE to “1”.

20.8

Serial Downloading

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 (out-

put). After RESET is set low, the Programming Enable instruction needs to be executed first

before program/erase operations can be executed. NOTE, in Table 20-13 on page 197, the pin

mapping for SPI programming is listed. Not all parts use the SPI pins dedicated for the internal

SPI interface.

Lock Bits

BS2

Fuse High Byte

BS1

DATA

Fuse Low Byte

BS2

Extended Fuse Byte

ATtiny48 Datasheet(PDF) 196 Page - ATMEL Corporation