ATmega32A Datasheet - Sunrom Technologies

ATmega32ATable 26-4.Fuse Low ByteFuse LowByte Bit No. Description Default ValueBODLEVEL 7 Brown-out Detector trigger level 1 (unprogrammed)BODEN 6 Brown-out Detector enable 1 (unprogrammed, BOD disabled)SUT1 5 Select start-up time 1 (unprogrammed) (1)SUT0 4 Select start-up time 0 (programmed) (1)CKSEL3 3 Select Clock source 0 (programmed) (2)CKSEL2 2 Select Clock source 0 (programmed) (2)CKSEL1 1 Select Clock source 0 (programmed) (2)CKSEL0 0 Select Clock source 1 (unprogrammed) (2)Notes: 1. The default value of SUT1:0 results in maximum start-up time. SeeTable 8-9 on page 30 fordetails.2. The default setting of CKSEL3:0 results in internal RC Oscillator @ 1MHz. See Table 8-1 onpage 26 for details.The status of the Fuse bits is not affected by Chip Erase. Note that the Fuse bits are locked ifLock bit1 (LB1) is programmed. Program the Fuse bits before programming the Lock bits.26.2.1 Latching of FusesThe Fuse values are latched when the device enters programming mode and changes of theFuse values will have no effect until the part leaves Programming mode. This does not apply tothe EESAVE Fuse which will take effect once it is programmed. The fuses are also latched onPower-up in Normal mode.26.3 Signature BytesAll Atmel microcontrollers have a three-byte signature code which identifies the device. Thiscode can be read in both serial and parallel mode, also when the device is locked. The threebytes reside in a separate address space.For the ATmega32A the signature bytes are:1. $000: $1E (indicates manufactured by Atmel)2. $001: $95 (indicates 32Kbytes Flash memory)3. $002: $02 (indicates ATmega32A device when $001 is $95)26.4 Calibration ByteThe ATmega32A stores four different calibration values for the internal RC Oscillator. Thesebytes resides in the signature row High Byte of the addresses 0x0000, 0x0001, 0x0002, and0x0003 for 1, 2, 4 , and 8Mhz respectively. During Reset, the 1MHz value is automaticallyloaded into the OSCCAL Register. If other frequencies are used, the calibration value has to beloaded manually, see “OSCCAL – Oscillator Calibration Register” on page 32“ for details.8155C–AVR–02/11269