ata6616 ATMEL Corporation, ata6616 Datasheet - Page 180

• Manufacturer Part Number: ata6616
• Description: Microcontroller With Lin Transceiver, 5v Regulator And Watchdog
• Manufacturer: ATMEL Corporation

4.15.3.5
4.15.4
4.15.4.1
4.15.4.2
4.15.4.3
4.15.4.4
4.15.4.5
180
ATA6616/ATA6617 [Preliminary]
Alternative USI Usage
Start Condition Detector
Half-duplex Asynchronous Data Transfer
4-bit Counter
12-bit Timer/Counter
Edge Triggered External Interrupt
Software Interrupt
The start condition detector is shown in Figure 4-67. The SDA line is delayed (in the range of 50
to 300 ns) to ensure valid sampling of the SCL line. The start condition detector is only enabled
in Two-wire mode.
The start condition detector is working asynchronously and can therefore wake up the processor
from the Power-down sleep mode. However, the protocol used might have restrictions on the
SCL hold time. Therefore, when using this feature in this case the Oscillator start-up time set by
the CKSEL Fuses (see
also be taken into the consideration. Refer to the USISIF bit description on page 182 for further
details.
When the USI unit is not used for serial communication, it can be set up to do alternative tasks
due to its flexible design.
By utilizing the USI Data Register in Three-wire mode, it is possible to implement a more com-
pact and higher performance UART than by software only.
The 4-bit counter can be used as a stand-alone counter with overflow interrupt. Note that if the
counter is clocked externally, both clock edges will generate an increment.
Combining the USI 4-bit counter and Timer/Counter0 allows them to be used as a 12-bit
counter.
By setting the counter to maximum value (F) it can function as an additional external interrupt.
The Overflow Flag and Interrupt Enable bit are then used for the external interrupt. This feature
is selected by the USICS1 bit.
The counter overflow interrupt can be used as a software interrupt triggered by a clock strobe.
Section 4.5.1 “Clock Systems and their Distribution” on page
DRAFT
9132A–AUTO–10/08
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