Atmel ATmega16/32/64/M1/C1
5. Wrong TSOFFSET manufacturing calibration value.
Erroneous value of TSOFFSET programmed in signature byte.
(TSOFFSET was introduced from REVB silicon).
Problem fix / workaround
To identify RevB with wrong TSOFFSET value, check device signature byte at address
0X3F if value is not 0X42 (Ascii code ‘B’) then use the following formula.
TS_OFFSET(True) = (150*(1-TS_GAIN))+TS_OFFSET.
6. PD0-PD3 set to outputs and PD4 pulled down following power-on with external
reset active.
At power-on with the external reset signal active the four I/O lines PD0-PD3 may be
forced into an output state. Normally these lines should be in an input state. PD4 may
be pulled down with internal 220 kOhm resistor. Following release of the reset line
(whatever is the startup time) with the clock running the I/Os PD0-PD4 will adopt their
intended input state.
Problem fix / workaround
None
7. LIN Break Delimitter
In SLAVE MODE, a BREAK field detection error can occur under following conditions.
The problem occurs if 2 conditions occur simultaneously:
a. The DOMINANT part of the BREAK is (N+0.5)*Tbit long with N=13, 14,15, ...
b. The RECESSIVE part of the BREAK (BREAK DELIMITER) is equal to 1*Tbit. (see
note below)
The BREAK_high is not detected, and the 2nd bit of the SYNC field is interpreted as the
BREAK DELIMITER. The error is detected as a framing error on the first bits of the PID
or on subsequent Data or a Checksum error.
There is no error if BREAK_high is greater than 1*Tbit + 18%.
There is no problem in Master mode.
Note:
LIN2.1 Protocol Specification paragraph 2.3.1.1 Break field says: “A break field is always gener-
ated by the master task(in the master node) and it shall be at least 13 nominal bit times of
dominant value, followed by a break delimiter, as shown in Figure 5-1. The break delimiter shall
be at least one nominal bit time long.”
Figure 5-1. The Break Field
Frame
Header
Response
Response space
Break
field
Sync
field
Protected
identifier
field
Data 1
Data 2
Data N
Checksum
Inter-byte space
Inter-byte space
Break
delimiter
Break
Workaround
None
21
7647ES–AVR–07/12
ATMEL [ ATMEL ]
