Rainbow-electronics ATmega8HVD Manuel d'utilisateur télécharger pdf (Page 131)

131

8052B–AVR–09/08

ATmega4HVD/8HVD

24.4 Calibration Bytes

The ATmega4HVD/8HVD has a calibration byte for the Fast RC Oscillator. This byte resides in

a high byte in the signature address space. During Reset, the calibration byte for the Fast RC

Oscillator is automatically written into the corresponding calibration register.

24.5 Page Size

24.6 Serial Downloading

Both the Flash and EEPROM memory arrays can be programmed using the serial SPI bus

while RESET

is pulled to GND. The serial interface consists of pins SCK, MOSI (input) and

MISO (output). After RESET

is set low, the Programming Enable instruction needs to be exe-

cuted first before program/erase operations can be executed. NOTE, in Table 24-8 on page

132, the pin mapping for SPI programming is listed. Not all parts use the SPI pins dedicated

for the internal SPI interface.

Figure 24-1. Serial Programming and Verify

Table 24-6. No. of Words in a Page and No. of Pages in the Flash

Device Flash Size Page Size PCWORD No. of Pages PCPAGE PCMSB

ATmega4HVD 2K words (4K bytes) 32 words PC[4:0] 64 PC[10:5] 10

ATmega8HVD 4K words (8K bytes) 32 words PC[4:0] 128 PC[11:5] 11

Table 24-7. No. of Words in a Page and No. of Pages in the EEPROM

Device EEPROM Size Page Size PCWORD No. of Pages PCPAGE EEAMSB

ATmega4HVD 256 bytes 4 bytes EEA[1:0] 64 EEA[7:2] 7

ATmega8HVD 256 bytes 4 bytes EEA[1:0] 64 EEA[8:2] 8

VFET

BATT

GND

SCK

MISO

MOSI

RESET

3.0 - 6.0V

1 2 ... 126 127 128 129 130 131 132 133 134 135 136 ... 167 168

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Rainbow-electronics ATmega8HVD Manuel d'utilisateur Page 131