AT32UC3C1512C Automotive Atmel Corporation, AT32UC3C1512C Automotive Datasheet - Page 432

• Manufacturer Part Number: AT32UC3C1512C Automotive
• Manufacturer: Atmel Corporation

22.4
22.4.1
22.4.2
22.4.3
22.4.4
22.5
22.5.1
22.5.2
9166C–AVR-08/11
Product Dependencies
Functional Description
Power Management
Clocks
Interrupt
Debug Operation
Enabling the SAU
Configuring the SAU Channels
In order to use this module, other parts of the system must be configured correctly, as described
below.
If the CPU enters a sleep mode that disables clocks used by the SAU, the SAU will stop func-
tioning and resume operation after the system wakes up from sleep mode.
The SAU has two bus clocks connected: One High Speed Bus clock (CLK_SAU_HSB) and one
Peripheral Bus clock (CLK_SAU_PB). These clocks are generated by the Power Manager. Both
clocks are enabled at reset, and can be disabled by writing to the Power Manager. The user has
to ensure that CLK_SAU_HSB is not turned off before accessing the SAU. Likewise, the user
must ensure that no bus access is pending in the SAU before disabling CLK_SAU_HSB. Failing
to do so may deadlock the High Speed Bus.
The SAU interrupt request line is connected to the interrupt controller. Using the SAU interrupt
requires the interrupt controller to be programmed first.
When an external debugger forces the CPU into debug mode, the SAU continues normal opera-
tion. If the SAU 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 SAU is enabled by writing a one to the Enable (EN) bit in the Control Register (CR). This will
set the SAU Enabled (EN) bit in the Status Register (SR).
The SAU has a set of channels, mapped in the HSB memory space. These channels can be
configured by a Remap Target Register (RTR), located at the same memory address. When the
SAU is in normal mode, the SAU channel is addressed, and when the SAU is in setup mode, the
RTR can be addressed.
Before the SAU can be used, the channels must be configured and enabled. To configure a
channel, the corresponding RTR must be programmed with the Remap Target Address. To do
this, make sure the SAU is in setup mode by writing a one to the Setup Mode Enable (SEN) bit
in CR. This makes sure that a write to the RTR address accesses the RTR, not the SAU chan-
nel. Thereafter, the RTR is written with the address to remap to, typically the address of a
specific PB register. When all channels have been configured, return to normal mode by writing
a one to the Setup Mode Disable (SDIS) in CR. The channels can now be enabled by writing
ones to the corresponding bits in the Channel Enable Registers (CERH/L).
The SAU is only able to remap addresses above 0xFFFC0000.
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