ATEVK1105 Atmel, ATEVK1105 Datasheet - Page 746

• Manufacturer Part Number: ATEVK1105
• Description: KIT EVAL FOR AT32UC3A0
• Manufacturer: Atmel
• Series: AVR®32r
• Type: MCUr

Specifications of ATEVK1105

• Contents: Evaluation Board, Software and Documentation
• Processor To Be Evaluated: AT32UC3A0512
• Processor Series: AVR
• Data Bus Width: 32 bit
• Interface Type: USART, TWI, USB, SPI, Ethernet
• Operating Supply Voltage: 3.3 V
• Silicon Manufacturer: Atmel
• Core Architecture: AVR
• Core Sub-architecture: AVR UC3
• Silicon Core Number: AT32UC3A0512
• Silicon Family Name: AVR
• Kit Contents: Board CD Docs
• Rohs Compliant: Yes
• For Use With/related Products: AT32UC3A0
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

36.6.4
36.6.4.1
32058J–AVR32–04/11
Service Access Bus
Busy reporting
instruction for the first time. SAMPLE/PRELOAD can also be used for taking a snapshot of the
external pins during normal operation of the part.
When using the JTAG interface for Boundary-Scan, the JTAG TCK clock is independent of the
internal chip clock, which is not required to run.
A number of private instructions are used to access Service Access Bus (SAB) resources. Each
of these are described in detail in SAB address map in the Service Access Bus chapter. The
MEMORY_SIZED_ACCESS instruction allows a sized read or write to any 36-bit address on the
bus. MEMORY_WORD_ACCESS is a shorthand instruction for 32-bit accesses to any 36-bit
address, while the NEXUS_ACCESS instruction is a Nexus-compliant shorthand instruction for
accessing the 32-bit OCD registers in the 7-bit address space reserved for these. These instruc-
tions require two passes through the Shift-DR TAP state: one for the address and control
information, and one for data.
To increase the transfer rate, consecutive memory accesses can be accomplished by the
MEMORY_BLOCK_ACCESS instruction, which only requires a single pass through Shift-DR for
data transfer only. The address is automatically incremented according to the size of the last
SAB transfer.
The access time to SAB resources depends on the type of resource being accessed. It is possi-
ble to read external memory through the EBI, in which case the latency may be very long. It is
possible to abort an ongoing SAB access by the CANCEL_ACCESS instruction, to avoid hang-
ing the bus due to an extremely slow slave.
"The access time to SAB resources depends on the type of resource being
accessed. It is possible to abort an ongoing SAB access by the
CANCEL_ACCESS instruction, to avoid hanging the bus due to an extremely
slow slave."
As the time taken to perform an access may vary depending on system activity and current chip
frequency, all the SAB access JTAG instructions can return a busy indicator. This indicates
whether a delay needs to be inserted, or an operation needs to be repeated in order to be suc-
cessful. If a new access is requested while the SAB is busy, the request is ignored.
The SAB becomes busy when:
The SAB becomes ready again when:
• Entering Update-DR in the address phase of any read operation, e.g. after scanning in a
• Entering Update-DR in the data phase of any write operation, e.g. after scanning in data for a
• Entering Update-DR during a MEMORY_BLOCK_ACCESS.
• Entering Update-DR after scanning in a counter value for SYNC.
• Entering Update-IR after scanning in a MEMORY_BLOCK_ACCESS if the previous access
• A read or write operation completes.
NEXUS_ACCESS address with the read bit set.
NEXUS_ACCESS write.
was a read and data was scanned after scanning the address.
AT32UC3A
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