AT91SAM7X128 Atmel, AT91SAM7X128 Datasheet - Page 286

• Manufacturer Part Number: AT91SAM7X128
• Description: MCU 32-Bit 91S ARM7TDMI RISC 128KB Flash 1.8V/3.3V 100-Pin LQFP
• Manufacturer: Atmel

Specifications of AT91SAM7X128

• Package: 100LQFP
• Device Core: ARM7TDMI
• Family Name: 91S
• Maximum Speed: 55 MHz
• Ram Size: 32 KB
• Program Memory Size: 128 KB
• Operating Supply Voltage: 1.8|3.3 V
• Data Bus Width: 32 Bit
• Program Memory Type: Flash
• Number Of Programmable I/os: 62
• Interface Type: CAN/Ethernet/SPI/I2S/TWI/USART/USB
• On-chip Adc: 8-chx10-bit
• Operating Temperature: -40 to 85 °C
• Number Of Timers: 3

29.5.5
29.5.5.1
Figure 29-10. Master Write with One, Two or Three Bytes Internal Address and One Data Byte
Figure 29-11. Master Read with One, Two or Three Bytes Internal Address and One Data Byte
286
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
AT91SAM7X512/256/128 Preliminary
S
S
S
Internal Address
7-bit Slave Addressing
DADR
DADR
DADR
DADR
DADR
DADR
W
W
W
The TWI interface can perform various transfer formats: Transfers with 7-bit slave address
devices and 10-bit slave address devices.
When Addressing 7-bit slave devices, the internal address bytes are used to perform random
address (read or write) accesses to reach one or more data bytes, within a memory page loca-
tion in a serial memory, for example. When performing read operations with an internal address,
the TWI performs a write operation to set the internal address into the slave device, and then
switch to Master Receiver mode. Note that the second start condition (after sending the IADR) is
sometimes called “repeated start” (Sr) in I2C fully-compatible devices. See
29-11
The three internal address bytes are configurable through the Master Mode register
(TWI_MMR).
If the slave device supports only a 7-bit address, i.e. no internal address, IADRSZ must be set to
0.
In the figures below the following abbreviations are used:
W
W
W
• S
• P
• W
• R
• A
• N
• DADR
• IADR
A
A
A
and
A
A
A
IADR(23:16)
IADR(15:8)
IADR(7:0)
Figure
IADR(23:16)
Start
Stop
Write
Read
Acknowledge
Not Acknowledge
Device Address
Internal Address
IADR(15:8)
IADR(7:0)
29-12.
A
A
A
IADR(15:8)
A
A
A
IADR(7:0)
S
DADR
IADR(15:8)
IADR(7:0)
DATA
A
A
R
IADR(7:0)
S
A
A
A
A
DADR
IADR(7:0)
P
DATA
DATA
A
S
R
A
A
A
N
DADR
DATA
P
DATA
P
DATA
Figure
6120H–ATARM–17-Feb-09
R
N
29-10,
A
P
A
N
P
P
Figure