ATMEGA88-20AUR Atmel, ATMEGA88-20AUR Datasheet - Page 273

• Manufacturer Part Number: ATMEGA88-20AUR
• Description: MCU AVR 8K FLASH 20MHZ 32TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA88-20AUR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 23
• Program Memory Size: 8KB (4K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

26.7
2545S–AVR–07/10
Addressing the Flash During Self-Programming
Table 26-4.
Note:
The Z-pointer is used to address the SPM commands.
Since the Flash is organized in pages (see
be treated as having two different sections. One section, consisting of the least significant bits, is
addressing the words within a page, while the most significant bits are addressing the pages.
This is1 shown in
addressed independently. Therefore it is of major importance that the Boot Loader software
addresses the same page in both the Page Erase and Page Write operation. Once a program-
ming operation is initiated, the address is latched and the Z-pointer can be used for other
operations.
The only SPM operation that does not use the Z-pointer is Setting the Boot Loader Lock bits.
The content of the Z-pointer is ignored and will have no effect on the operation. The LPM
instruction does also use the Z-pointer to store the address. Since this instruction addresses the
Flash byte-by-byte, also the LSB (bit Z0) of the Z-pointer is used.
Bit
ZH (R31)
ZL (R30)
BOOTRST
1
0
1. “1” means unprogrammed, “0” means programmed
Boot Reset Fuse
Z15
15
Z7
7
Reset Address
Reset Vector = Application Reset (address 0x0000)
Reset Vector = Boot Loader Reset (see
Figure
Z14
14
Z6
6
26-3. Note that the Page Erase and Page Write operations are
(1)
Z13
13
Z5
5
Table 27-9 on page
Z12
12
Z4
4
Z11
11
Z3
Table 26-6 on page
3
ATmega48/88/168
Z10
10
Z2
2
288), the Program Counter can
280)
Z9
Z1
9
1
Z8
Z0
8
0
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