AT32UC3L064_1 ATMEL [ATMEL Corporation], AT32UC3L064_1 Datasheet - Page 763

• Manufacturer Part Number: AT32UC3L064_1
• Description: AVR32 32-bit Microcontroller
• Manufacturer: ATMEL [ATMEL Corporation]

31.5.3.6
31.5.3.7
32099A–AVR32–06/09
CANCEL_ACCESS
SYNC
Table 31-22. MEMORY_BLOCK_ACCESS Details (Continued)
The overhead using block word access is 4 cycles per 32 bits of data, resulting in an 88% trans-
fer efficiency, or 2.1 MBytes per second with a 20 MHz TCK frequency.
If a very slow memory location is accessed during a SAB memory access, it could take a very
long time until the busy bit is cleared, and the SAB becomes ready for the next operation. The
CANCEL_ACCESS instruction provides a possibility to abort an ongoing transfer and report a
timeout to the JTAG master.
When the CANCEL_ACCESS instruction is selected, the current access will be terminated as
soon as possible. There are no guarantees about how long this will take, as the hardware may
not always be able to cancel the access immediately. The SAB is ready to respond to a new
command when the busy bit clears.
Starting in Run-Test/Idle, CANCEL_ACCESS is accessed in the following way:
Table 31-23. CANCEL_ACCESS Details
This instruction allows external debuggers and testers to measure the ratio between the external
JTAG clock and the internal system clock. The SYNC data register is a 16-bit counter that
counts down to zero using the internal system clock. The busy bit stays high until the counter
reaches zero.
Starting in Run-Test/Idle, SYNC instruction is used in the following way:
Instructions
DR input value (Data write phase)
DR output value (Data read phase)
DR output value (Data write phase)
Instructions
IR input value
IR output value
DR Size
DR input value
DR output value
1. Select the IR Scan path.
2. In Capture-IR: The IR output value is latched into the shift register.
3. In Shift-IR: The instruction register is shifted by the TCK input.
4. Return to Run-Test/Idle.
1. Select the IR Scan path.
2. In Capture-IR: The IR output value is latched into the shift register.
3. In Shift-IR: The instruction register is shifted by the TCK input.
4. Return to Run-Test/Idle.
5. Select the DR Scan path.
Details
dddddddd dddddddd dddddddd dddddddd xx
eb dddddddd dddddddd dddddddd dddddddd
xx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxeb
Details
10011 (0x13)
peb01
1
x
0
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