Datasheet

206
XMEGA A1U [DATASHEET]
Atmel-8385H-AVR-ATxmega64A1U-128A1U-Datasheet–AVR–04/2014
Problem fix/Workaround
Allocate 1024bytes RAM buffer when using 1023 isochronous endpoint. This workaround is implemented in all
USB software and source code delivered from Atmel in the AVR Software Framework.
9. USB endpoint table is 16-byte alignment
The USB endpoint table uses 16-byte alignment, instead of 16-bit alignment.
Problem fix/Workaround
Align the endpoint configuration table pointer in SRAM to a 16-byte. This workaround is implemented in all
USB software and source code delivered from Atmel in the AVR Software Framework.
10. USB Auto ZLP feature is non-functional
The Auto ZLP feature is non-functional and can not be used.
Problem fix/Workaround
None.
11. Disabling the USART transmitter does not automatically set the TxD pin direction to input
If the USART transmitter is idle with no frames to transmit, setting TXEN to zero will not automatically set the
TxD pin direction to input.
Problem fix/Workaround
The TxD pin direction can be set to input using the Port pin direction to input using the port direction (DIR) reg-
ister. When the port pin direction is input, it will be immediate and ongoing transmissions will be truncated.
12. TWI, SDAHOLD configuration in the TWI CTRL register is one bit
The SDAHOLD configuration in the TWI Control register (CTRL) is one bit. Due to this the SDA hold time can
be configured for maximum ~50ns when enabled. Configuring for longer hold time will have no effect.
Problem fix/Workaround
If longer SDA hold time than 50nS is required it must be handled in software.
13. ADC has increased INL error in when used in SE unsigned mode at low temperatures
When the ADC is used on single ended (SE) unsigned mode, -INL error is increased up to +/- 5 LSB in temper-
atures below -20C.
Problem fix/Workaround
Use the ADC in single ended signed mode.
14. ADC is non-functional in SE unsigned mode with V
REF
below 1.8V
When the ADC is used on single ended unsigned mode and V
REF
is below 1.8V, INL and DNL error is
increased above +/- 10LSB, i.e. the ADC have missing codes under this condition.
Problem fix/Workaround
Use the ADC in single ended signed mode.