5. Errata
5.1
Errata Summary
5.1.1
ATmega32M1/C1 Rev. C (Mask Revision)
• The AMPCMPx bits return 0
5.1.2
5.1.3
5.1.4
ATmega32M1/C1 Rev. B (Mask Revision)
• The AMPCMPx bits return 0
• No comparison when amplifier is used as comparator input and ADC input
• CRC calculation of diagnostic frames in LIN 2.x.
• Wrong TSOFFSET manufacturing calibration value
• PD0-PD3 set to outputs and PD4 pulled down following power-on with external reset active.
ATmega32M1/C1 Rev. A (Mask Revision)
• Inopportune reset of the CANIDM registers.
• The AMPCMPx bits return 0
• No comparison when amplifier is used as comparator input and ADC input
• CRC calculation of diagnostic frames in LIN 2.x.
• PD0-PD3 set to outputs and PD4 pulled down following power-on with external reset active.
Errata Description
1. Inopportune reset of the CANIDM registers
After the reception of a CAN frame in a MOb, the ID mask registers are reset.
Problem fix / workaround
Before enabling a MOb in reception, re-initialize the ID mask registers - CANIDM[4..1].
2. The AMPCMPx bits return 0
When they are read the AMPCMPx bits in AMPxCSR registers return 0.
Problem fix / workaround
If the reading of the AMPCMPx bits is required, store the AMPCMPx value in a variable in
memory before writing in the AMPxCSR register and read the variable when necessary.
3. No comparison when amplifier is used as comparator input and ADC input
When it is selected as ADC input, an amplifier receives no clock signal when the ADC is
stopped. In that case, if the amplifier is also used as comparator input, no analog signal is
propagated and no comparison is done.
Problem fix / workaround
Select another ADC channel rather than the working amplified channel.
4. CRC calculation of diagnostic frames in LIN 2.x.
Diagnostic frames of LIN 2.x use “classic checksum” calculation. Unfortunately, the setting
of the checksum model is enabled when the HEADER is transmitted/received. Usually, in
LIN 2.x the LIN/UART controller is initialized to process “enhanced checksums” and a slave
task does not know what kind of frame it will work on before checking the ID.
Problem fix / workaround
This workaround is to be implemented only in case of transmission/reception of diagnostics
frames.
20
ATmega16/32/64/M1/C1
7647DS–AVR–08/08
ATMEL [ ATMEL ]
