ATTINY43U-SUR Atmel, ATTINY43U-SUR Datasheet - Page 105

• Manufacturer Part Number: ATTINY43U-SUR
• Description: MCU AVR 4KB FLASH 8MHZ 20SOIC
• Manufacturer: Atmel
• Series: AVR® ATtinyr

Specifications of ATTINY43U-SUR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 8MHz
• Connectivity: USI
• Peripherals: Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 16
• Program Memory Size: 4KB (2K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 64 x 8
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 4x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

8048B–AVR–03/09
Figure 14-4. Two-wire Mode Operation, Simplified Diagram
The data direction is not given by the physical layer. A protocol, like the one used by the TWI-
bus, must be implemented to control the data flow.
Figure 14-5. Two-wire Mode, Typical Timing Diagram
Referring to the timing diagram
1. The start condition is generated by the master by forcing the SDA low line while keep-
SDA
SCL
SLAVE
MASTER
ing the SCL line high (A). SDA can be forced low either by writing a zero to bit 7 of the
USI Data Register, or by setting the corresponding bit in the PORTA register to zero.
Note that the Data Direction Register bit must be set to one for the output to be
enabled. The start detector logic of the slave device (see
Bit7
Bit7
Bit6
Bit6
S
A B
Bit5
Bit5
C
ADDRESS
Bit4
Bit4
1 - 7
Bit3
Bit3
R/W
Bit2
Bit2
(Figure
8
D
Bit1
Bit1
14-5), a bus transfer involves the following steps:
ACK
9
Bit0
Bit0
E
DATA
1 - 8
Two-wire Clock
ACK
Control Unit
9
Figure 14-6 on page
PORTxn
DATA
1 - 8
HOLD
SCL
SDA
SCL
SDA
SCL
ACK
9
106)
F
P
VCC
105