Figure 35. Serial Programming Waveforms
Table 19. Serial Programming Instruction Set for AT90S1200
Instruction Format
Instruction
Byte 1
Byte 2
Byte 3
Byte4
Operation
Programming
Enable
1010 1100 0101 0011 xxxx xxxx xxxx xxxx Enable serial programming while RESET is low.
Chip Erase
1010 1100 100x xxxx xxxx xxxx xxxx xxxx Chip erase both Flash and EEPROM memory
arrays.
Read Program
Memory
0010 H000 0000 000a bbbb bbbb oooo oooo Read H (high or low) byte o from program memory at
word address a:b.
Write Program
Memory
0100 H000 0000 000a bbbb bbbb iiii iiii Write H (high or low) byte i to program memory at
word address a:b.
Read EEPROM 1010 0000 0000 0000 00bb bbbb oooo oooo Read data o from EEPROM memory at address b.
Memory
Write EEPROM 1100 0000 0000 0000 00bb bbbb iiii iiii Write data i to EEPROM memory at address b.
Memory
Write Lock Bits
1010 1100 1111 1211 xxxx xxxx xxxx xxxx Write Lock bits. Set bits 1,2 = “0” to program Lock
bits.
Read Signature 0011 0000 xxxx xxxx xxxx xxbb oooo oooo Read signature byte o from address b.(1)
Byte
Note:
a = address high bits, b = address low bits, H = 0 – Low byte, 1 – High byte, o = data out, i = data in, x = don’t care, 1 = Lock
Bit 1, 2 = Lock Bit 2
Note:
1. The signature bytes are not readable in lock mode 3 (i.e., both Lock bits programmed).
46
AT90S1200
0838H–AVR–03/02
ATMEL [ ATMEL ]
