Rainbow Electronics ATtiny12 - Manual (Page 45)

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ATtiny11/12
1006C–09/01
• CKSEL3..0 fuses: See Table 3, “Device Clocking Options Select,” on page 5 and
Table 9, “ATtiny12 Clock Options and Start-up Times,” on page 20, for which
combination of CKSEL3..0 to use. Default value is “0010”, internal RC oscillator with
long start-up time.
The status of the fuse bits is not affected by Chip Erase.
Note: 1. If the RSTDISBL Fuse is programmed, then the programming hardware should apply
+12V to PB5 while the ATtiny12 is in Power-on Reset. If not, the part can fail to enter
programming mode caused by drive contention on PB0 and/or PB5.
Signature Bytes All Atmel microcontrollers have a three-byte signature code which identifies the device.
The three bytes reside in a separate address space.
For the ATtiny11 they are:
1. $000: $1E (indicates manufactured by Atmel)
2. $001: $90 (indicates 1 Kb Flash memory)
3. $002: $04 (indicates ATtiny11 device when signature byte $001 is $90)
For the ATtiny12 (1) they are:
1. $000: $1E (indicates manufactured by Atmel)
2. $001: $90 (indicates 1 Kb Flash memory)
3. $002: $05 (indicates ATtiny12 device when signature byte $001 is $90)
Note: 1. When both lock bits are programmed (Lock mode 3), the Signature Bytes can not be
read in the Low-voltage Serial mode. Reading the Signature Bytes will return: $00,
$01 and $02.
Calibration Byte in
ATtiny12 The ATtiny12 has a one-byte calibration value for the internal RC oscillator. This byte
resides in the high byte of address $000 in the signature address space. During memory
programming, the external programmer must read this location and program its value
into a selected location in the normal Flash Program memory. At start-up, the user soft-
ware must read this Flash location and write the value to the OSCCAL register.
Programming the Flash
and EEPROM
ATtiny11 Atmel’s ATtiny11 offers 1K bytes of Flash Program memory.
The ATtiny11 is shipped with the on-chip Flash Program memory array in the erased
state (i.e., contents = $FF) and ready to be programmed.
This device supports a High-voltage (12V) Serial programming mode. Only minor cur-
rents (<1 mA) are drawn from the +12V pin during programming.
The program memory array in the ATtiny11 is programmed byte-by-byte.
ATtiny12 Atmel’s ATtiny12 offers 1K bytes of in-system reprogrammable Flash Program memory
and 64 bytes of in-system reprogrammable EEPROM Data memory.
The ATtiny12 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 high-voltage (12V) serial programming mode and a low-voltage
serial programming mode. The +12V is used for programming enable only, and no cur-
rent of significance is drawn by this pin. The Low-voltage Serial Programming mode