ATmega16HVB Atmel Corporation, ATmega16HVB Datasheet - Page 192

• Manufacturer Part Number: ATmega16HVB
• Manufacturer: Atmel Corporation

Specifications of ATmega16HVB

• Flash (kbytes): 16 Kbytes
• Pin Count: 44
• Max. Operating Frequency: 8 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 8
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 17
• Ext Interrupts: 15
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 12
• Adc Speed (ksps): 1.9
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 1
• Eeprom (bytes): 512
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 4.0 to 25
• Operating Voltage (vcc): 4.0 to 25
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 4
• Input Capture Channels: 2
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

29.6
29.7
192
Entering the boot loader program
Addressing the flash during self-programming
ATmega16HVB/32HVB
Entering the Boot Loader takes place by a jump or call from the application program. This may
be initiated by a trigger such as a command received via the TWI interface. Alternatively, the
Boot Reset Fuse can be programmed so that the Reset Vector is pointing to the Boot Flash start
address after a reset. In this case, the Boot Loader is started after a reset. After the application
code is loaded, the program can start executing the application code. Note that the fuses cannot
be changed by the MCU itself. This means that once the Boot Reset Fuse is programmed, the
Reset Vector will always point to the Boot Loader Reset and the fuse can only be changed
through the serial or parallel programming interface.
Table 29-2.
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 is shown in
are 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
Figure 29-3 on page
Z15
15
Z7
7
Reset address
Reset vector = Application reset (address 0x0000)
Reset vector = Boot loader reset (see
Z14
Z6
14
6
(1)
.
Z13
13
Z5
5
193. Note that the Page Erase and Page Write operations
”Fuse bits” on page
Z12
Z4
12
4
Table 29-5 on page
Z11
11
Z3
3
Z10
10
Z2
2
205), the Program Counter can
200)
Z9
Z1
9
1
Z8
Z0
8
0
8042D–AVR–10/11