ATmega88PA Automotive Atmel Corporation, ATmega88PA Automotive Datasheet - Page 219

• Manufacturer Part Number: ATmega88PA Automotive
• Manufacturer: Atmel Corporation

22.5
22.5.1
9223B–AVR–09/11
Overview of the TWI Module
SCL and SDA Pins
The TWI module is comprised of several submodules, as shown in
drawn in a thick line are accessible through the AVR data bus.
Figure 22-9. Overview of the TWI Module
These pins interface the AVR TWI with the rest of the MCU system. The output drivers contain
a slew-rate limiter in order to conform to the TWI specification. The input stages contain a
spike suppression unit removing spikes shorter than 50 ns. Note that the internal pull-ups in
the AVR pads can be enabled by setting the PORT bits corresponding to the SCL and SDA
pins, as explained in the I/O Port section. The internal pull-ups can in some systems eliminate
the need for external ones.
Atmel ATmega48PA/88PA/168PA [Preliminary]
Slew-rate
Address Match Unit
Arbitration detection
Control
START / STOP
Address Comparator
Address Register
Control
SCL
(TWAR)
Spike
Filter
Bus Interface Unit
Spike Suppression
Address/Data Shift
Register (TWDR)
Slew-rate
Control
SDA
Status Register
Ack
Spike
Filter
(TWSR)
State Machine and
Control Unit
Status control
Bit Rate Generator
Control Register
Bit Rate Register
Figure
Prescaler
(TWCR)
(TWBR)
22-9. All registers
219