# US 7,411,913 B2 · Process for automatically detecting the throughput of a network, particularly of the can bus type and for configuring with the detected throughput by transition analysis, and corresponding device

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- Number: US 7,411,913 B2
- Document ID: US7411913B2
- Status: Granted
- Kind: B2
- Application number: 11/039,175
- Filed: 2005-01-19
- Published: 2005-08-18
- Granted: 2008-08-12
- Earliest claimed: 2004-01-20
- Assignees: Atmel Nantes SA
- Inventors: Laurentiu Birsan; Marc Laurent; Thierry Delalande; Jean-Sebastien Berthy
- Web page: https://patentgrep.com/patent/US7411913B2

## CPC

- H04L 12/4135: {using bit-wise arbitration}
- H04L 41/082: the condition being updates or upgrades of network functionality
- H04L 41/0869: Validating the configuration within one network element
- H04L 2012/40215: {Controller Area Network CAN}
- H04L 2012/40273: {the transportation system being a vehicle}
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

A process for automatically detecting and configuring with the throughput of a network, in which a device: (a) goes into a listen mode; (b) obtains a triplet of successive transitions in a transmitted signal, the triplet delimiting first and second signal levels, one dominant and the other recessive; (c) measures the duration of each of the first and second levels; (d) as a function of the measured durations, obtains a new throughput configuration by determining values for parameters that define a bit length LBIT; (e) validates the new throughput configuration; (g) if at least one throughput adaptation condition is verified, goes into a normal mode, otherwise obtains a next transition of the signal, which delimits with the last previous transition a new level of the signal, then measures the duration of the new level and reiterates steps (d) to (g) taking account of the new signal level.

## Claims

### Claim 1

A process for automatically detecting the throughput of a network and for configuring with the detected throughput via a device connected to the network, the network transmitting a signal on which messages are carried that include bits of length LBIT and of a dominant or recessive type, wherein in the process comprises the following successive steps:
a) the device goes into a listen mode, in which it is able to receive messages coming from the network but is unable to send messages on the network;
b) the device obtains a triplet of successive transitions in the signal transmitted on the network, said triplet delimiting a first and second signal level, one dominant and the other recessive;
c) the device measures the duration, expressed as multiples of device clock period TH, of each of the first and second levels;
d) as a function of the measured lengths of the signal levels, the device obtains a new throughput configuration by determining values for parameters that define the bit length LBIT;
e) the device validates the new throughput configuration; and
g) if the device detects that at least one throughput adaptation condition is verified, it goes into a normal mode, otherwise it obtains a next transition of the signal, which delimits with the last previous transition a new level of the signal, it measures the duration of the new level, expressed as multiples of device clock period TH, and it reiterates steps (d) to (g) taking account of the new signal level.

### Claim 2 (depends on 1)

The process according to claim 1, wherein the network is a CAN bus, and the device includes a CAN microcontroller completed relative to a conventional CAN microcontroller so as to implement the process according to the invention for automatically detecting the throughput of the network and for configuring with the detected throughput.

### Claim 3 (depends on 2)

The process according to claim 2, the bit length LBIT being defined by:
a scalar BRP, such that: TQ=BRP*TH with TQ a unit of time and TH the period of the device clock;
lengths expressed as a number of time units TQ: length LSYNC of a synchronisation segment, length LPRS of a propagation segment for the purpose of compensating for a physical delay on the CAN bus, lengths LPHS1 and LPHS2 of first and second phase segments allowing a sample point to be positioned,
wherein the step (d) itself includes the following steps:
(d0) the device updates two log registers, in such a way that:
after the first iteration of step (d), the registers contain the minimum P and the maximum G respectively of the durations of the first and second levels;
after each successive iteration of step (d), the registers are updated according to the following equation: if G<X, then G assumes the value X, otherwise P assumes the value X, with X the duration of the new signal level;
d(1) as a function of the content P and G of said log registers, the device obtains a number m allowing the bit length LBIT to be expressed as a function of the period TH of the device clock:
LBIT=m*TH;
(d2) as a function of the previously obtained number m, the device obtains a maximum value BRPMAX of the scalar BRP knowing that:
i) LBIT=m*TH =n*BRP*TH, hence: m=n* BRP
ii) n=LBIT/TQ
iii) n≦MAX, with nMAX a pre-set maximum number of time units TQ that the bit length LBIT may include;
(d3) as a function of the number m and of the maximum value BRPMAX previously obtained, the device obtains a value of the number n such that: n=m/BRPMAX;
(d4) as a function of the number n previously obtained, the device obtains values for the length LSYNC of the synchronization segment, the length LPRS of the propagation segment and lengths LPHS1 and LPHS2 of the first and second phase segments.

### Claim 4 (depends on 3)

The process according to claim 3, wherein, in step (d1), the value of the number m is given by the following equations:
m=min(2P−G, G−P), if P<G<2P,
m=min(G−2P,P), if 2P<G<6P,
m=P/2, if G=2P,
m is not calculated in the other cases.

### Claim 5 (depends on 4)

The process according to claim 4, wherein, in step (d1), the conditions for applying the equations giving the value of the number m are modified as follows:
m=min(2P−G, G−P), if P+P/k<G≦2(P−P/k),
m=min(G−2P,P), if 2(P+P/k)<G<6(P−P/k),
m=P/2, if 2(P−P/k)<G≦2(P+P/k),
m is not calculated in the other cases,
with k a pre-set whole number greater than or equal to 4, and preferentially equal to 8.

### Claim 6 (depends on 3)

The process according to claim 3, wherein, in step (d4), a pre-set correspondence table is used, associating with each value of the number n a set of values for the length LSYNC of the synchronisation segment, the length LPRS of the propagation segment and the lengths LPHS1 and LPHS2 of the first and second phase segments.

### Claim 7 (depends on 1)

The process according to claim 1, wherein said at least one throughput adaptation condition in step (g) is the correct receipt of a message coming from the network.

### Claim 8 (depends on 1)

The process according to claim 1, wherein the step (g) is preceded by the following step:
(f) if the device detects the proper receipt of the useful part of a message coming from the network, it provisionally goes into normal mode to send an acknowledgement field on the network then goes back to listen mode, otherwise it obtains a next transition of the signal, which delimits with the last previous transition a new signal level, it measures the duration of the new level, expressed as multiples of device clock period TH, and it reiterates steps (d) to (g) taking account of the new signal level.

### Claim 9

A device intended to be connected to a network, wherein the device includes means for automatically detecting the network throughput and for configuring with the detected throughput, the network transmitting a signal on which messages are carried including bits of length LBIT and of dominant or recessive type, and wherein the device further includes:
means for toggling from a normal mode to a listen mode, in which means are activated for blocking messages sent by the device to the network, the device continuing to receive messages coming from the network;
means for obtaining a triplet of successive transitions in the signal transmitted on the network, said triplet delimiting a first and second level of the signal, one dominant and the other recessive;
means for measuring the duration, expressed as multiples of device clock period TH, of each of the first and second signal levels;
means for obtaining, as a function of the measured durations of the signal levels, a new throughput configuration by determining values for parameters that define the bit length LBIT;
means for validating the new throughput configuration;
means for detecting that at least one throughput adaptation condition is verified;
means for toggling from listen mode to normal mode, activated in the event of positive detection by the detection means;
means for obtaining a next signal transition, which delimits with the last previous transition a new signal level, and means for measuring the duration of the new level, expressed as multiples of device clock period TH, activated with said means for obtaining and validating a new throughput configuration and said means for detecting that at least one throughput adaptation condition is verified, in the event of negative detection by the detection means, in such a way as to take account of the new signal level.

### Claim 10 (depends on 9)

The device according to claim 9, wherein the network is a CAN bus, and the device includes a CAN microcontroller completed relative to a conventional CAN microcontroller and itself including said means for automatically detecting the throughput of the network and for configuring with the detected throughput.

### Claim 11 (depends on 10)

The device according to claim 10, wherein the means for toggling from normal mode to listen mode include means for generating a mode selection signal, assuming the value “0” or “1” depending on whether the device is to operate in normal mode or listen mode respectively,
wherein the completed CAN microcontroller includes a modified conventional CAN microcontroller so as to itself include said means for automatically detecting the throughput of the network and for configuring with the detected throughput, apart from said means for blocking sent messages,
and wherein the means for blocking sent messages include means for embodying the “OR” logic function between the mode selection signal and the send signal of the modified conventional CAN microcontroller, the output signal of the means for embodying the “OR” logic function constituting the send signal of the completed CAN microcontroller.

### Claim 12 (depends on 11)

The device according to claim 11, wherein the device includes loop means from the output to the input of the modified conventional CAN microcontroller, including:
means for embodying the “AND” logic function between the second signal of the modified conventional CAN microcontroller and the receive signal of the completed CAN microcontroller;
multiplexing means receiving at a first input the output signal of the means for embodying the “AND” logic function and at a second input the receive signal of the completed CAN microcontroller, the output signal of the multiplexing means constituting the receive signal of the modified conventional CAN microcontroller, the multiplexing means being controlled by the mode selection signal in such a way that the first and second input is selected depending on whether the mode selection signal assumes the value “1” or “0” respectively.

### Claim 13 (depends on 10)

The device according to claim 10, wherein the completed CAN microcontroller additionally includes means for provisionally toggling from listen mode to normal mode, so as to send an acknowledgement field on the network.

### Claim 14 (depends on 13)

The device according to claim 13 wherein the means for provisionally toggling from listen mode to normal mode include means for generating a signal for provisionally deactivating the mode selection signal, assuming the value “0” or “1” depending on whether the mode selection signal is to be provisionally deactivated or not.