AT32UC3A1512-AUR Atmel, AT32UC3A1512-AUR Datasheet - Page 83

• Manufacturer Part Number: AT32UC3A1512-AUR
• Description: MCU 32BIT 512KB FLASH 100-TQFP
• Manufacturer: Atmel
• Series: AVR®32 UC3r

Specifications of AT32UC3A1512-AUR

• Core Processor: AVR
• Core Size: 32-Bit
• Speed: 66MHz
• Connectivity: Ethernet, I²C, SPI, SSC, UART/USART, USB OTG
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 69
• Program Memory Size: 512KB (512K x 8)
• Program Memory Type: FLASH
• Ram Size: 64K x 8
• Voltage - Supply (vcc/vdd): 1.65 V ~ 1.95 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 100-TQFP, 100-VQFP
• For Use With: ATAVRONEKIT - KIT AVR/AVR32 DEBUGGER/PROGRMMR770-1008 - ISP 4PORT ATMEL AVR32 MCU SPIATSTK600-TQFP100 - STK600 SOCKET/ADAPTER 100-TQFPATEVK1100 - KIT DEV/EVAL FOR AVR32 AT32UC3A
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

AT32UC3A
RETS behaves incorrectly when MPU is enabled and MPU is configured so that
system stack is not readable in unprivileged mode.
Fix/Woraround
Workaround 1: Make system stack readable in unprivileged mode,
or
Workaround 2: Return from supervisor mode using rete instead of rets. This
requires :
1. Changing the mode bits from 001b to 110b before issuing the instruction.
Updating the mode bits to the desired value must be done using a single mtsr
instruction so it is done atomically. Even if this step is described in general
as not safe in the UC technical reference guide, it is safe in this very
specific case.
2. Execute the RETE instruction.
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