Datasheet

952

32142D–06/2013

ATUC64/128/256L3/4U

38.5.12 aWire

1. aWire MEMORY_SPEED_REQUEST command does not return correct CV

The aWire MEMORY_SPEED_REQUEST command does not return a CV corresponding to

the formula in the aWire Debug Interface chapter.

Fix/Workaround

Issue a dummy read to address 0x100000000 before issuing the

MEMORY_SPEED_REQUEST command and use this formula instead:

38.5.13 Flash

5. Corrupted data in flash may happen after flash page write operations

After a flash page write operation from an external programmer, reading (data read or code

fetch) in flash may fail. This may lead to an exception or to others errors derived from this

corrupted read access.

Fix/Workaround

Before any flash page write operation, each write in the page buffer must preceded by a

write in the page buffer with 0xFFFF_FFFF content at any address in the page.

38.5.14 I/O Pins

1. PA05 is not 3.3V tolerant.

PA05 should be grounded on the PCB and left unused if VDDIO is above 1.8V.

Fix/Workaround

None.

2. No pull-up on pins that are not bonded

PB13 to PB27 are not bonded on UC3L0256/128, but has no pull-up and can cause current

consumption on VDDIO/VDDIN if left undriven.

Fix/Workaround

Enable pull-ups on PB13 to PB27 by writing 0x0FFFE000 to the PUERS1 register in the

GPIO.

3. PA17 has low ESD tolerance

PA17 only tolerates 500V ESD pulses (Human Body Model).

Fix/Workaround

Care must be taken during manufacturing and PCB design.

sab

CV 3–

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