Receiver with adaptive strobe offset adjustment
Receiver for receiving a data stream via a data bus, which receiver samples the bits of the data stream in an over-sampling process, in which n bit strobe offsets are used and n data sets with i bits are sampled,—applies a decision criterion for identifying those data sets with correct bit values. This decision uses checksum CRC,—selects one of the identified data sets with correct bit values and—uses the bit strobe offset, which was used for receiving the selected data streams, for receiving the data stream. In this way the multiphase clock with optimal phase shifts is selected.
1. Receiver for receiving a data stream having a plurality of bits via a data bus, comprising:
a sampler which performs an over-sampling process on the bits of the data stream, in which n bit strobe offsets are used and m data sets with i bits are sampled,
an identifier which applies a decision criterion to identify those data sets with correct bit values,
a selector which selects one of the identified data sets with correct bit values,
wherein the receiver uses the bit strobe offset which was used for receiving the selected data stream for receiving the data stream.
2. Receiver according to claim 1 , which uses a transmitted checksum as the decision criterion for identifying the data sets with correct bit values.
3. Receiver according to claim 1 , which uses a decision algorithm for selecting a data set from those identified data sets with correct bit values, the algorithm selecting the data set that is located in the middle of the identified data sets.
4. Receiver according to claim 1 , which uses a decision algorithm for selecting a data set from those identified data sets with correct bit values, the algorithm selecting the data set that is determined by averaging over weighted bit strobe offsets which correspond to the identified data sets.
5. Receiver according to claim 1 , which uses a decision algorithm for selecting a data set from those identified data sets with correct bit values, the algorithm canceling those data sets of the identified data sets, which have been sampled at that end of the offset variation of the sampling process, in which more wrong data sets appear than on the other end, and selecting the data set that is located at a middle position of the remaining data sets.
6. Receiver according to claim 1 , which uses a decision algorithm for selecting a data set from those identified data sets with correct bit values, the algorithm selecting a data set p of the identified data sets sampled with a predefined strobe value, if its bit values are correct, and otherwise selecting the data set with correct bit values sampled with the closest strobe value to the strobe value of data set p.
7. Receiver according to claim 1 for receiving a data stream according to the FlexRay standard, which receiver uses the bits of the header CRC of the data stream for the selection of the best strobe offset value.
8. A method for receiving a data stream having a plurality of bits via a data bus, comprising the steps of:
sampling the bits of the data stream in an over-sampling process, in which n bit strobe offsets are used and m data sets with i bits are sampled,
applying a decision criterion to identify those data sets with correct bit values,
selecting one of the identified data sets with correct bit values, and
using the bit strobe offset which was used for receiving the selected data stream for receiving the data stream.
9. The method according to claim 8 , further comprising:
using a transmitted checksum as the decision criterion for identifying the data sets with correct bit values.
10. The method according to claim 8 , further comprising:
using a decision algorithm for selecting a data set from those identified data sets with correct bit values, the algorithm selecting the data set that is located in the middle of the identified data sets.
11. The method according to claim 8 , further comprising:
using a decision algorithm for selecting a data set from those identified data sets with correct bit values, the algorithm selecting the data set that is determined by averaging over weighted bit strobe offsets which correspond to the identified data sets.
12. The method according to claim 8 , further comprising:
using a decision algorithm for selecting a data set from those identified data sets with correct bit values, the algorithm canceling those data sets of the identified data sets, which have been sampled at that end of the offset variation of the sampling process, in which more wrong data sets appear than on the other end, and selecting the data set that is located at a middle position of the remaining data sets.
13. The method according to claim 8 , further comprising:
using a decision algorithm for selecting a data set from those identified data sets with correct bit values, the algorithm selecting a data set p of the identified data sets sampled with a predefined strobe value, if its bit values are correct, and otherwise selecting the data set with correct bit values sampled with the closest strobe value to the strobe value of data set p.
14. The method according to claim 8 for receiving a data stream according to the FlexRay standard, which method uses the bits of the header CRC of the data stream for the selection of the best strobe offset value.