SAM7S256_14 Datasheet, PDF (615/775 Pages) ATMEL Corporation – ARM-based Flash MCU

40.6.2.5 ADC: GOVRE Bit is not Updated
Read of the Status Register at the same instant as an end of conversion leads to skipping the update of the
GOVRE (general overrun) flag. GOVRE is neither reset nor set.
For example, if reading the status while an end of conversion is occurring and:
1. GOVRE is active but DRDY is inactive, does not correspond to a new general overrun condition but the
GOVRE flag is not reset.
2. GOVRE is inactive but DRDY is active, does correspond to a new general overrun condition but the
GOVRE flag is not set.
Problem Fix/Workaround
None
40.6.2.6 ADC: GOVRE Bit is not Set when Reading CDR
When reading CDRy (Channel Data Register y) at the same instant as an end of conversion on channel “x” with the
following conditions:
• EOC[x] already active,
• DRDY already active,
• GOVRE inactive,
• previous data stored in LCDR being neither data from channel “y”, nor data from channel “x”.
GOVRE should be set but is not.
Problem Fix/Workaround
None
40.6.2.7 ADC: GOVRE Bit is not Set when Disabling a Channel
When disabling channel “y” at the same instant as an end of conversion on channel “x”, EOC[x] and DRDY being
already active, GOVRE does not rise.
Note: OVRE[x] rises as expected.
Problem Fix/Workaround
None
40.6.2.8 ADC: OVRE Flag Behavior
When the OVRE flag (on channel i) has been set but the related EOC status (of channel i) has been cleared (by a
read of CDRi or LCDR), reading the Status register at the same instant as an end of conversion (causing the set of
EOC status on channel i), does not lead to a reset of the OVRE flag (on channel i) as expected.
Problem Fix/Workaround:
None
40.6.2.9 ADC: EOC Set although Channel Disabled
If a channel is disabled while a conversion is running and if a read of CDR is performed at the same time as an end
of conversion of any channel occurs, the EOC of the channel with the conversion running may rise (whereas it has
been disabled).
Problem Fix/Workaround
Do not take into account the EOC of a disabled channel
SAM7S Series [DATASHEET]
6175M–ATARM–26-Oct-12
615