ATmega48 Automotive Atmel Corporation, ATmega48 Automotive Datasheet - Page 257

• Manufacturer Part Number: ATmega48 Automotive
• Manufacturer: Atmel Corporation

Specifications of ATmega48 Automotive

• Flash (kbytes): 4 Kbytes
• Pin Count: 32
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 12
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 23
• Ext Interrupts: 24
• Usb Speed: No
• Usb Interface: No
• Spi: 2
• Twi (i2c): 1
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 0.5
• Eeprom (bytes): 256
• Self Program Memory: NO
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 125
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 3
• Output Compare Channels: 6
• Input Capture Channels: 1
• Pwm Channels: 6
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

23.0.3
23.1
7530I–AVR–02/10
Addressing the Flash During Self-Programming
Performing a Page Write
To execute Page Write, set up the address in the Z-pointer, write “00000101” to SPMCSR and
execute SPM within four clock cycles after writing SPMCSR. The data in R1 and R0 is ignored.
The page address must be written to PCPAGE. Other bits in the Z-pointer must be written to
zero during this operation.
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 is shown in
addressed independently. Therefore it is of major importance that the software addresses the
same page in both the Page Erase and Page Write operation.
The LPM instruction uses 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.
Figure 23-1. Addressing the Flash During SPM
Note:
Bit
ZH (R31)
ZL (R30)
• The CPU is halted during the Page Write operation.
Z - REGISTER
1. The different variables used in
PROGRAM MEMORY
BIT
PAGE
PROGRAM
COUNTER
15
Z15
15
Z7
7
Figure
PAGE ADDRESS
WITHIN THE FLASH
ZPCMSB
PCMSB
Z14
Z6
14
24-3. Note that the Page Erase and Page Write operations are
6
PCPAGE
Z13
13
Z5
5
ATmega48/88/168 Automotive
Figure 24-3
ZPAGEMSB
PAGEMSB
Table 25-12 on page
PCWORD
Z12
12
Z4
4
WORD ADDRESS
WITHIN A PAGE
(1)
are listed in
1
Z11
0
0
11
Z3
3
INSTRUCTION WORD
PAGE
Table 25-12 on page
Z10
10
Z2
2
284), the Program Counter can
Z9
Z1
9
1
PCWORD[PAGEMSB:0]:
00
01
02
PAGEEND
284.
Z8
Z0
8
0
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