268
AT90PWM216/316 [DATASHEET]
7710H–AVR–07/2013
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.
24.3.1
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.
24.4
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.
24.4.1
Signature Bytes
For the AT90PWM216/316 the signature bytes are:
1.
0x000: 0x1E (indicates manufactured by Atmel).
2.
0x001: 0x94 (indicates 16KB Flash memory).
3.
0x002: 0x83 (indicates AAT90PWM216/316 device when 0x001 is 0x94).
24.5
Calibration Byte
The AT90PWM216/316 has a byte calibration value for the internal RC Oscillator. This byte resides in the high byte
of address 0x000 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.
24.6
Parallel Programming Parameters, Pin Mapping, and Commands
This section describes how to parallel program and verify Flash Program memory, EEPROM Data memory, Mem-
ory Lock bits, and Fuse bits in the AT90PWM216/316. Pulses are assumed to be at least 250 ns unless otherwise
noted.
24.6.1
Signal Names
In this section, some pins of the AT90PWM216/316 are referenced by signal names describing their functionality
during parallel programming, see
Figure 24-1 and
Table 24-7. Pins not described in the following table are refer-
enced by pin names.
The XA1/XA0 pins determine the action executed when the XTAL1 pin is given a positive pulse. The bit coding is
When pulsing WR or OE, the command loaded determines the action executed. The different Commands are