AT32UC3C2512C Automotive Atmel Corporation, AT32UC3C2512C Automotive Datasheet - Page 733

• Manufacturer Part Number: AT32UC3C2512C Automotive
• Manufacturer: Atmel Corporation

28.7.2
28.7.3
28.7.4
28.7.5
28.7.6
28.8
28.8.1
9166C–AVR-08/11
Functional Description
Power Management
Clocks
DMA
Interrupts
Debug Operation
Transfer Format
If the CPU enters a sleep mode that disables clocks used by the TWIS, the TWIS will stop func-
tioning and resume operation after the system wakes up from sleep mode. The TWIS is able to
wake the system from sleep mode upon address match, see
The clock for the TWIS bus interface (CLK_TWIS) is generated by the Power Manager. This
clock is enabled at reset, and can be disabled in the Power Manager. It is recommended to dis-
able the TWIS before disabling the clock, to avoid freezing the TWIS in an undefined state.
The TWIS DMA handshake interface is connected to the Peripheral DMA Controller. Using the
TWIS DMA functionality requires the Peripheral DMA Controller to be programmed after setting
up the TWIS.
The TWIS interrupt request lines are connected to the interrupt controller. Using the TWIS inter-
rupts requires the interrupt controller to be programmed first.
When an external debugger forces the CPU into debug mode, the TWIS continues normal oper-
ation. If the TWIS is configured in a way that requires it to be periodically serviced by the CPU
through interrupts or similar, improper operation or data loss may result during debugging.
The data put on the TWD line must be 8 bits long. Data is transferred MSB first; each byte must
be followed by an acknowledgement. The number of bytes per transfer is unlimited (see
28-4 on page
Each transfer begins with a START condition and terminates with a STOP condition (see
28-3).
Figure 28-3.
• A high-to-low transition on the TWD line while TWCK is high defines the START condition.
• A low-to-high transition on the TWD line while TWCK is high defines a STOP condition.
734).
START and STOP Conditions
TWCK
TWD
Start
Section 28.8.8 on page
Stop
AT32UC3C
741.
Figure
Figure
733