Rainbow Electronics AT90C8534 - Manual (Page 38)

AT90C8534
38
Note: n: 6, 5, …, 0, pin number.
Memory Programming
Program and Data Memory Lock Bits
The AT90C8534 MCU provides two Lock bits that can be left unprogrammed (“1”) or can be programmed (“0”) to obtain the
additional features listed in Table 10.
Note: The Lock bits can only be erased with the Chip Erase command.
Signature Bytes
All Atmel microcontrollers have a 3-byte signature code that identifies the device. The three bytes reside in a separate
address space.
For the AT90C8534 they are:
1. $00: $1E (indicates manufactured by Atmel)
2. $01: $93 (indicates 8 KB Flash memory)
3. $02: $04 (indicates AT90C8534 device when $01 is $93)
Programming the Flash and EEPROM
Atmel’s AT90C8534 offers 8K bytes of Flash program memory and 512 bytes of EEPROM data memory.
The AT90C8534 is shipped with the on-chip Flash program and EEPROM data memory arrays in the erased state
(i.e., contents = $FF) and ready to be programmed. This device supports a parallel programming mode, enabled by the
PEN pin.
The program and data memory arrays on the AT90C8534 are programmed byte-by-byte.
Parallel Programming
This section describes how to parallel program and verify Flash program memory, EEPROM data memory and memory
Lock bits in the AT90C8534.
Table 9. DDAn Effects on Port A Pins
DDAn PORTAn Comment
0 0 Tri-state (high-Z)
0 1 Tri-state (high-Z)
1 0 Push-pull Zero Output
1 1 Push-pull One Output
Table 10. Lock Bit Protection Modes
Memory Lock Bits
Protection Type Mode LB1 LB2
1 1 1 No memory lock features enabled.
2 0 1 Further programming of the Flash and EEPROM is disabled.
3 0 0 Same as mode 2 and verify is also disabled.