Datasheet

362
ATmega16U4/32U4 [DATASHEET]
Atmel-7766J-USB-ATmega16U4/32U4-Datasheet_04/2016
Note: 1. “XX” is don’t care. The letters refer to the programming description above.
28.6.5 Programming the EEPROM
The EEPROM is organized in pages, see Table 28-12 on page 359. When programming the EEPROM, the
program data is latched into a page buffer. This allows one page of data to be programmed simultaneously. The
programming algorithm for the EEPROM data memory is as follows (refer to “Programming the Flash” on
page 360 for details on Command, Address and Data loading):
1. A: Load Command “0001 0001”.
2. G: Load Address High Byte (0x00 - 0xFF).
3. B: Load Address Low Byte (0x00 - 0xFF).
4. C: Load Data (0x00 - 0xFF).
5. E: Latch data (give PAGEL a positive pulse).
K: Repeat 3 through 5 until the entire buffer is filled
L: Program EEPROM page
1. Set BS2, BS1 to “00”.
2. Give WR
a negative pulse. This starts programming of the EEPROM page. RDY/BSY goes low.
3. Wait until to RDY/BSY
goes high before programming the next page (See Figure 28-4 on page 362 for
signal waveforms).
Figure 28-4. Programming the EEPROM Waveforms
28.6.6 Reading the Flash
The algorithm for reading the Flash memory is as follows (refer to “Programming the Flash” on page 360 for
details on Command and Address loading):
1. A: Load Command “0000 0010”.
2. H: Load Address Extended Byte (0x00- 0xFF).
3. G: Load Address High Byte (0x00 - 0xFF).
4. B: Load Address Low Byte (0x00 - 0xFF).
5. Set OE
to “0”, and BS1 to “0”. The Flash word low byte can now be read at DATA.
6. Set BS to “1”. The Flash word high byte can now be read at DATA.
7. Set OE
to “1”.
RDY/BSY
WR
OE
RESET +12V
PAGEL
BS2
0x11 ADDR. HIGH
DATA
ADDR. LOW DATA ADDR. LOW DATA XX
XA1
XA0
BS1
XTAL1
XX
AGBCEB C EL
K