at91sam9g20-cu ATMEL Corporation, at91sam9g20-cu Datasheet - Page 423

• Manufacturer Part Number: at91sam9g20-cu
• Description: At91 Arm Thumb Microcontrollers
• Manufacturer: ATMEL Corporation

Figure 31-11. Master Write with One, Two or Three Bytes Internal Address and One Data Byte
Figure 31-12. Master Read with One, Two or Three Bytes Internal Address and One Data Byte
31.7.6.2
6384B–ATARM–15-Dec-08
TWD
TWD
TWD
TWD
TWD
TWD
Three bytes internal address
Two bytes internal address
One byte internal address
Three bytes internal address
Two bytes internal address
One byte internal address
S
S
S
S
S
S
10-bit Slave Addressing
DADR
DADR
DADR
DADR
DADR
DADR
W
W
W
For a slave address higher than 7 bits, the user must configure the address size (IADRSZ) and
set the other slave address bits in the internal address register (TWI_IADR). The two remaining
Internal address bytes, IADR[15:8] and IADR[23:16] can be used the same as in 7-bit Slave
Addressing.
Example: Address a 10-bit device (10-bit device address is b1 b2 b3 b4 b5 b6 b7 b8 b9 b10)
Figure 31-13
the use of internal addresses to access the device.
Figure 31-13. Internal Address Usage
1. Program IADRSZ = 1,
2. Program DADR with 1 1 1 1 0 b1 b2 (b1 is the MSB of the 10-bit address, b2, etc.)
3. Program TWI_IADR with b3 b4 b5 b6 b7 b8 b9 b10 (b10 is the LSB of the 10-bit
W
W
W
A
A
A
address)
IADR(23:16)
A
A
A
IADR(15:8)
IADR(7:0)
below shows a byte write to an Atmel AT24LC512 EEPROM. This demonstrates
IADR(23:16)
IADR(15:8)
IADR(7:0)
S
T
A
R
T
M
S
B
Address
Device
A
A
A
0
IADR(15:8)
Sr
IADR(7:0)
A
A
A
S
B
L
W
W
R
E
R
T
I
/
DADR
A
C
K
WORD ADDRESS
IADR(15:8)
IADR(7:0)
M
S
B
DATA
FIRST
A
A
R
Sr
AT91SAM9G20 Preliminary
IADR(7:0)
A
C
A
A
A
A
K
WORD ADDRESS
DADR
SECOND
IADR(7:0)
P
DATA
DATA
A
L
S
B
Sr
R
A
C
K
A
A
N
A
DADR
DATA
DATA
P
P
DATA
DATA
A
C
K
R
N
S
O
P
T
P
N
A
A
P
P
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