at90pwm81-16se ATMEL Corporation, at90pwm81-16se Datasheet - Page 252

• Manufacturer Part Number: at90pwm81-16se
• Description: 8-bit Avr Microcontroller With 8k Bytes In- System Programmable Flash
• Manufacturer: ATMEL Corporation

22.2.3
22.3
22.3.1
22.4
22.5
22.5.1
252
Signature Bytes
Calibration Byte
Parallel Programming Parameters, Pin Mapping, and Commands
AT90PWM81
Latching of Fuses
Signature Bytes
Signal Names
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.
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, the signature row.
For the AT90PWM81 the signature bytes are:
The AT90PWM81 has a byte calibration value for the internal RC Oscillator. This byte resides in the byte
of address 0x003 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.
This section describes how to parallel program and verify Flash Program memory, EEPROM Data mem-
ory, Memory Lock bits, and Fuse bits in the AT90PWM81. Pulses are assumed to be at least 250 ns unless
otherwise noted.
In this section, some pins of the AT90PWM81 are referenced by signal names describing their functional-
ity during parallel programming, see
are referenced by pin names.
The XA1/XA0 pins determine the action executed when the XTAL1 pin is given a positive pulse. The bit
coding is shown in
When pulsing WR or OE, the command loaded determines the action executed. The different Commands
are shown in
1.
2.
3.
0x000: 0x1E (indicates manufactured by Atmel).
0x002: 0x93 (indicates 8KB Flash memory).
0x004: 0x88 (indicates AT90PWM81 device when 0x002 is 0x93).
Table
Table
22-10.
22-9.
Figure 22-1
and
Table
22-7. Pins not described in the following table
7734M–AVR–03/10