Rainbow-electronics ATmega103L Manuel d'utilisateur télécharger pdf (Page 95)

ATmega603/103

Enter Programming Mode

The following algorithm puts the device in parallel programming mode:

1. Apply supply voltage according to Table 37, between V

and GND.

2. Set RESET

and BS1 pins to ‘0’ and wait at least 100 ns.

3. Apply 11.5 - 12.5V to RESET

. Any activity on BS1 within 100 ns after +12V has been applied to RESET, will cause

the device to fail entering programming mode.

Chip Erase

The Chip Erase will erase the Flash and EEPROM memories, and Lock bits. The Lock bits are not reset until the program

memory has been completely erased. The Fuse bits are not changed. A chip erase must be performed before the Flash or

EEPROM is reprogrammed.

Load Command “Chip Erase”

1. Set XA1, XA0 to ‘10’. This enables command loading.

2. Set BS1 to ‘0’.

3. Set DATA to ‘1000 0000’. This is the command for Chip erase.

4. Give XTAL1 a positive pulse. This loads the command.

5. Give WR

a t

WLWH_CE

wide negative pulse to execute Chip Erase. See Table 41 for t

WLWH_CE

value. Chip Erase does

not generate any activity on the RDY/BSY

pin.

Table 40. 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

0000 1000 Read Signature Bytes

0000 0100 Read Lock and Fuse Bits

0000 0010 Read Flash

0000 0011 Read EEPROM

Table 41. Minimum WR pulse width for chip erase

Symbol 3.2V 3.6V 4.0V 5.0V

WLWH_CE

56 ms 43 ms 35 ms 22 ms

1 2 ... 90 91 92 93 94 95 96 97 98 99 100 ... 125 126

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Rainbow-electronics ATmega103L Manuel d'utilisateur Page 95