Rainbow Electronics ATmega64L - Manual (Page 255)

255
ATmega16(L)
2466B–09/01
Notes: 1. The default value of SUT1..0 results in maximum start-up time. SeeTable 10 on page
27 for details.
2. The default setting of CKSEL3..0 results in internal RC oscillator @ 1MHz. See Table
2 on page 23 for details.
The status of the Fuse bits is not affected by Chip Erase. Note that the Fuse bits are
locked if lock bit1 (LB1) is programmed. Program the Fuse bits before programming the
Lock bits.
Latching of Fuses The fuse values are latched when the device enters programming mode and changes of
the fuse values will have no effect until the part leaves programming mode. This does
not apply to the EESAVE fuse which will take effect once it is programmed. The fuses
are also latched on power-up in normal mode.
Signature Bytes All Atmel microcontrollers have a three-byte signature code which identifies the device.
This code can be read in both serial and parallel mode, also when the device is locked.
The three bytes reside in a separate address space.
For the ATmega16 the signature bytes are:
1. $000: $1E (indicates manufactured by Atmel)
2. $001: $94 (indicates 16KB Flash memory)
3. $002: $03 (indicates ATmega16 device when $001 is $94)
Calibration Byte The ATmega16 has a byte calibration value for the internal RC Oscillator. This byte
resides in the high byte of address $000 in the signature address space. During reset,
this byte is automatically written into the OSCCAL register to ensure correct frequency
of the calibrated RC oscillator.
Parallel Programming
Parameters, Pin
Mapping, and
Commands This section describes how to parallel program and verify Flash Program memory,
EEPROM Data memory, Memory Lock bits, and Fuse bits in the ATmega16. Pulses are
assumed to be at least 250ns unless otherwise noted.
Signal Names In this section, some pins of the ATmega16 are referenced by signal names describing
their functionality during parallel programming, see Figure 128 and Table 107. Pins not
described in the following table are referenced by pin names.
Table 106. Fuse Low Byte
Fuse Low
Byte Bit
No. Description Default Value
BODLEVEL 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)