Rainbow Electronics AT90S2313 - Manual (Page 70)

70
AT90S2313
0839I–AVR–06/02
Data Polling Flash When a byte is being programmed into the Flash, reading the address location being
programmed will give the value $7F. At the time the device is ready for a new byte, the
programmed value will read correctly. This is used to determine when the next byte can
be written. This will not work for the value $7F, so when programming this value, the
user will have to wait for at least t
WD_PROG
before programming the next byte. As a chip-
erased device contains $FF in all locations, programming of addresses that are meant
to contain $FF can be skipped.
Figure 54. Serial Programming Waveforms
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.
Table 28. Serial Programming Instruction Set
Instruction
Instruction Format
Operation Byte 1 Byte 2 Byte 3 Byte4
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 Flash and EEPROM
memory arrays.
Read Program Memory
0010 H000 xxxx xxaa bbbb bbbb oooo oooo Read H (high or low) data o from
program memory at word address
a:b.
Write Program Memory
0100 H000 xxxx xxaa bbbb bbbb iiii iiii Write H (high or low) data i to
program memory at word address
a:b.
Read EEPROM
Memory 1010 0000 xxxx xxxx xbbb bbbb oooo oooo Read data o from EEPROM memory
at address b.
Write EEPROM
Memory 1100 0000 xxxx xxxx xbbb bbbb iiii iiii Write data i to EEPROM memory at
address b.
Write Lock Bits
1010 1100 111x x 21 x xxxx xxxx xxxx xxxx Write Lock bits. Set bits 1,2 = “0” to
program Lock bits.
Read Signature Bytes 0011 0000 xxxx xxxx xxxx xxbb oooo oooo Read signature byte o at address b. (1)