Rainbow-electronics ATmega8515L Bedienungsanleitung PDF herunterladen (Seite 191)

191

ATmega8515(L)

2512A–AVR–04/02

Data Polling EEPROM Whenanewbyte hasbeen written and isbeing programmed into EEPROM, reading the

address location being programmedwill give thevalue $FF.Atthetimethe deviceis

ready for anewbyte, the programmed value will readcorrectly.This is used to deter-

mine when thenext byte can be written. Thiswill not work for thevalue $FF, but theuser

should have the following in mind: As a chip eraseddevice contains$FFin all locations,

programming of addresses that are meant to contain $FF, can be skipped.Thisdoes

not apply if the EEPROM isreprogrammedwithout chip-erasing the device. Inthiscase,

data polling cannot beusedfor thevalue $FF, and theuserwill have to wait at least

WD_EEPROM

before programming thenext byte. See Table 93 for t

WD_EEPROM

value.

Figure 84. Serial Programming Waveforms

Table 93. Minimum Wait DelayBefore Writing the Next Flash orEEPROM Location

Symbol Minimum Wait Delay

WD_FLASH

4.5 ms

WD_EEPROM

9.0 ms

WD_ERASE

9.0 ms

MSB

LSB

SERIAL CLOCK INPUT

(SCK)

SERIAL DATA INPUT

(MOSI)

(MISO)

SAMPLE

SERIAL DATA OUTPUT

1 2 ... 186 187 188 189 190 191 192 193 194 195 196 ... 222 223

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Rainbow-electronics ATmega8515L Bedienungsanleitung Seite 191