These tests allow checking of:
- differential voltage;
- common-mode voltage variations;
- rise and fail times;
- recessive and dominant currents.
RO/Di
o I
I
Frequency: 20 kHz Duty cycle: 50 I
E = l r B ransmltte
Oscilloscope B.P. 50 MHz min.
o
A B
L I 1 I
LI
- D i f t e r e n t i a l probe
-
50 R 50 R
470 pF
Oscilloscope B.P. - 50 MHz min.
ln I
9 yo ;fterentiai 470 pF
probe
Figure 52 - Differential voltage measurement
_ _ _ _ _ ~
I S 0 11517 P T * 3 74 4851703 O565353 0 5 9
IS0 11519-3:1994(E)
Frequency: 20 kHz Duty cycle: 50 94
E = l
Figure 53 - Measurement of common-mode voltage variation
L
Test setup
S O R 50n
1 50 R
I
50 R l
+ s v
+ 5 v
Figure 54 - Measurement of T I and T2
IS0 11519 P T U 3 94 4851903 0 5 6 5 3 5 2 T ợ 5 m
IS0 11519-3:1994(E)
DE
DATA
DATA
I in position 1 I in position 2
I I I I
I I
I I I
I I I
I I I
l
I -
Figure 55 - Timing diagram for figure54
IS0 L L 5 L 9 P T * 3 9 4 m 4853903 0565353 9 2 3 M
IS0 11519-3:1994(E)
DE
D A T A
- D A T A
~ I IIII IIII
I I I
I I I -
I I I l I I l I I I I I
I I I
I L
I I I
I , I
Figure 56 - Determination of propagation times
I S 0 11517 P T * 3 94 4851903 0565354 868
I
150 n
DE
I S 0 11519-3:1994(E)
4,s v t o 5.5 v
Measurement o f 1 mA current
Figure 57 - Current measurement method
I S 0 3 3 5 3 9 P T * 3 9 4 4853903 0 5 b 5 3 5 5 7 T 4 D
IS0 11 51 9-3:1994( E)
Annex A (nor mat ive)
Setup example for Baud Rate Multiplier
Signals f r o m line
tronsmitter receiver > Counter
- I S t a r t
detector Memory
H Local >
illill
B.R.M
H corrected
Figure A.l - Baud Rate Multiplier
IS0 31519 P T x 3 94 = 4853903 0565356 630 I S 0 1 151 9-3:1994( E)
Annex B (norma tive)
Setup example of realization of interface between physical layer and data link layer
B.l Interface position/OSI model
In order to simplify the hardware of the communication interface, a new sublayer structure has been defined. This new substructure does not strictly correspond to the model used in this part of I S 0 11 51 9.
The example of the realization of the interface layer between physical and MAC layers described in this annex corresponds to the breakdown of layers in accordance with figure B.1.
The MAC sublayer contains the access mechanism to the physical layer which assures the transfer between the two LLC entities.
The physical sublayer directly connected to the MAC sublayer performs the electric encoding and decoding of bits and symbols (characters).
B.2 Definition of dialogue signals between binary and electric encoding/decoding sublayers
Figure 6.2 illustrates the breakdown of layers and gives the various signals allowing interfacing of the different su blaye rs.
As each symbol corresponds to an integer number of binary elements and as the bit time unit is equal to two time slots (T.S.) for the Manchester-L code (see figures 30 and 31 1 and 1 T.S. for the Enhanced Manchester code (see figures 30 to 32 1, each character is coded for each time unit which corresponds to one binary element with the signals classified in figure 8.2 and defined in table B.1.
B.3 Coding bit and symbol (see 7.2.3)
The PL2 physical sublayer uses the binary information bit to transmit (BT) and transmission code violation (TCV) to generate the various characters of different fields, and uses the bit received (BR), reception code violation (RCV) and collision detection (CDì signals to read the different received characters.
In case of the Enhanced Manchester code, the physical layer automatically inserts every 3 NRZ bits a Manchester-L bit from the start of the identifier fields (see 6.2) until the End Of Data field inclusive.
From the ACK field until the next SOF, the PL1 physical sublayer follows the code defined in table B.2.
Figures B.3 and B.4 describe the specific dialogue between the physical layer and the data link layer for the SOF.
The Hsyn clock signal presents the same temporal characteristics as the Hsymb. (See figures 32 and 33.) Tables B.2 and B.3 define the correspondence between the dialogue signals of the physical layer and the data link layer.
B.4 Character synchronization
The synchronization of characters are based on the same synchronization rules regardless of the bit or the binary value of symbol.
The electrical synchronization is based on the rules described in 7.2.4.2.
I S 0 11519 P T * 3 94 4853903 O565357 577
IS0 11519-3:1994(E)
Application Presentation Session Transport Network Data link
Physical
- -IS
-
MAC
Scope o f the document
U
Acceptance filter Frame test Data encapsulation/
decapsula tion
~ ~~
Serializing Medium access control function
Binary
encoding/decoding of characters
Electric encoding/
decoding of characters synchronization
I 1 - 2 I
I 1-1 I
Line interface
Connector parameters Medium parameters
Beyondthescopeofthedocument
Supervisor
Unsuccessful attempt count Repeat attempt count
Line break (bus status)
7
Figure B.l - Breakdown by layers in accordance with OS1 model
IS0 L L 5 L ù P T * 3 94 4851903 0 5 b 5 3 5 8 403
Bus error
IS0 11519-3:1994(E)
PL1 to PL2
0-Clock e r r o r
o1 0-Bus error
0-Hsyn
O0 0-Bit t o transmit
0-Transmission code
Control Viola tion
0-Bit received 0-Reception code Violation 0-Collision detection
Bit to trans- mit
Trans- mission code Bit received
Electric
encoding/decoding o f characters
PL2 to PL1
PL2 to PL1
PL1 to PL2
M-Clock e r r o r M-Bus e r r o r M-Hsyn
M-Bit to transmit M-Transmission code Violation
M-Bit received M-Reception code Violation
M-Collision detection
Reception code viol- ation
Binary
encoding/decoding of characters
PL1 to PL2
Figure 6.2 - Interconnections between different sublayers
Tab Direction
Hsyn PL1 to PL2
tection
B.l - Dialogue signals between sublayers PL1 and PL2 Definition
Signal indicating a clock corrector overflow.
Signal indicating the presence of a dominant level of longer duration than the Start Of Frame symbol.
Synchronized clock which enables PL2 to generate characters and to recognize the charac- ters received.
Binary value of next bit or (part of) symbol to transmit.
Signal which permits disabling and enabling of electric coding of each binary value to be sent.
Binary value of the bit or (part of) symbol read on the bus.
Signal indicating a rule violation in the corresponding bit code (Manchester-L or Enhanced Manchester).
Signal, updated at each received bit, which indicates that a collision has occurred (transmit bit different than received bit).
IS0 11519 PT*3 9 4 = 4851903 0 5 6 5 3 5 7 3 4 T
IS0 11519-3:1994[E)
Table B.2 - Physical layer
I Emission
I Reception
-
BT
- O
- O
T u n Dominant bit i I
Table B.3 - Data link layer
Signal on bus Enhanced Manchester
Dominant bit uncoding D
Dominant bit
u NRZ coding
O
Manchester O
Recessive bit uncoding O
Recessive bit coding O
Manchest e r D
BT: Bit to Transmit TCV: Transmission
Code Violation BR: Bit Received RCV: Reception Code
Violation R: Recessive level D: Dominant level
BT: Bit to Transmit TCV: Transmission
Code Violation BR: Bit Received RCV: Reception Code
Violation R: Recessive level D: Dominant level
IS0 11519 P T * 3 9 4 4851903 0565360 Ob1
I I I I I I I
I I
! H c o r
I
Synchronization counter
Edge received Resynchronization point
Transmission point
Hsyn
Collision detection and bit l e v e l sampling Acquisition by PL2 o f received value (BR. RCV. CD) Acquisition by PL1 o f next value t o be transmitted (ET. TCV) Transmit bit presented b y t h e P L 2 s u b l a y e r
Received bit presented by the PL1 sublayer
3
The value must be stable [prior t o this signal
I
i111 1 1 1 1 1 1 1 1 1
The value must be stable prior to this signal
Figure B.3 - Bit synchronization: Bit NRZ
Hcor
Synchronization counter
Edge received Resynchronization point
Collision detection and time slot level sampling Sampling o f time slot l e v e l - bit validation -
error indication Transmission point
Hsyn
Acquisition by PL2 o f
IS0 11519 P T * 3 94 rn 4853903 0565363 T T 8 rn
IS0 11519-3:1994(E)
I l l l l l l l l l l l l l l l l l l I I I I I l I I I I I I I I
I I l I I I I I I
4 8 12 16 20 24 2 8 32
I I I I I l I I l
l l
I I I I I I I I I I l l I I
I l
I I
II I I
Il t t
H l
received value (BR, RCV. CO) Acquisition by PL1 of next value to be transmitted (BT, TCV)
bit counter incrementing B i t t o transmit pre- sented by the PL2 sublayer
The value must be stable prior t o this signal
Received bit presented by the PL1 sublayer
Possible delay time about d r i f t o t clocks between 2 edges received
The value m u s t be stable prior t o this signal
Figure B.4 - Bit synchronization: Bit Manchester
IS0 1 1 5 1 9 P T * 3 9 4 = 4851903 05b53b2 93Y
IS0 115193:1994(E)
I I l
B.5 Signals exchange rules between PL1 and PL2 sublayers
The rules governing the exchanges between PL1 and PL2 sublayers are based on the use of the Hsyn clock:
- The acquisition of the signals from the PL2 sublayer to the PL1 sublayer must be made on the rising edge of Hsyn.
I
- At the interface, these signals must be present a t least half a corrected clock period (Hcor) before the syn- chronized clock (Hsyn) appears.
- The acquisition of the signals from the PL1 sublayer to the PL2 sublayer must be made on the falling edge of
- At the interface, these signals must be present a t least half a corrected clock period (Hcor) before the syn- Hsyn.
chronized clock (Hsyn) appears. See figure 8.5.
6.6 Exceptions to this signal exchange rules
Two signals can be acquired or generated asynchronously:
- the clock error signal,
- the bus error signal.
The time duration must be a t least superior to the synchronized clock period (H syn).
B.7 Timing diagram for various dialogue signals between PL1 and PL2 sublayers
See figure B.6.
Hcor
Hsyn a e
a I e
Transmitted data by PL1 to PL2
Transmitted data by PL2 to PL1
Figure 8.5 - Information exchange rule between PL1 and PL2 sublayer
Hcor
1
Hsyn
B T
TCV
I ----
BR
RCV
CD
Signal on bus
IS0 11519 P T * 3 94 = it851903 0565363 8 7 0 W
IS0 11519-3:1994(E)
I l I I I I l I I l I I I I
O 16 32 k a 64 ao 96 112 128 141, 160 176 192 208
1 O
1 O
1 ----
I
IS0 11519 P T * 3 94 4853903 0565364 7 0 7 W
Hcor
Hsyn
B T
TCV
BR
RCV
CO
1
O
Signal on bus
I I I I I I I I I I I I l I
O 16 32 48 64 80 96 112 128 144 160 176 192 208
Figure B.7 - Dialogue for signalling reception of SOF in Enhanced Manchester
Hcor
FCS Hsyn
EOD ACK EOF I IFS
BT
TCV
BR
RCV
C U
Signai on bus
1 O 1 O
1 O
1 O
1 O
1 O
I S 0 3 3 5 1 9 P T * 3 9 4 m 4 8 5 3 7 0 3 0565365 643 m
I S 0 11519-3:1994(E)
I I I I I I I I I I I I I I I I I
O 32 64 96 128 160 192 224
I I
Figure B.8 - Dialogue for generation of End Of Frame with positive acknowledgement reception in Enhanced Manchester
IS0 11519 P T * 3 9 4 H 4853903 O565366 5 8 T IS0 115193:1994(E)
Hcor
I I I I I I I I I I I I I I I I I
O 32 6 4 96 128 160 192 224
Hsyn
1 O ET
1 O TCV
1 O ER
1 O RCV
CO
Signal on bus
1 O
1 O
Not ACK
FCS EDO ACK EOF I IFS
Figure B.9 - Dialogue for generation of End of Frame without positive acknowledgement reception in Enhanced Manchester
Hcor
Hsyn
B T
TCV
ER
RCV
CO
Signal on bus
O
IS0 I11519 P T * 3 9 4 4851903 0565367 4Lb
IS0 11519-3:1994(E)
I I I I I I I I I I I I I I I I I
O 32 6 4 96 128 160 192 224
I I
I 1
Positive ACK
FCS EO0 ACK EOF I IFS
Figure B.10 - Dialogue for signalling reception of End Of Frame with positive acknowledgement reception in Enhanced Manchester
IS0 LL5L9 P T r 3 94 m 4 8 5 3 9 0 3 0565368 3 5 2 m
FCS EO0
Hcor
ACK EOF I IFS
Hsyn
B T
TCV
BR
RCV
C O
Signai on bus
1 O 1 O 1 O 1 O 1 O
1 O
I I I I I I I I I I I I I I I I I
O 32 64 96 128 160 192 224
Figure B . l l - Dialogue for signalling reception of End of Frame without positive acknowledgement reception in Enhanced Manchester
Hcor
IS0 LL5L9 P T + 3 94 4853903 O565369 299
IS0 11519-3:1994(E)
I I I I I I I I I I I I I I I I I
O 32 66 96 128 160 192 224
Hsyn
1
BT
O
1 O TCV
1 O BR
I RCV
O I
CO
1
O I I
1 O Signal on bu5
I V i o l I EOF I IFS
Figure B.12 - Dialogue when violation of code occurs in Enhanced Manchester
IS0 LL5L9 P T * 3 94 œ 4853903 0 5 b 5 3 7 0 TOD œ
I
IS0 11519-3:1994(E)
I
Hcor
Hsyn
B T
TCV
BR
RCV
CO
Signal on bus
1 O
1 O
1 O
1 O 1 O 1 O
~~
I l I I I I I I I I I I I I I I I
O 32 6 4 96 128 160 192 224
I
I
I I
Figure B.13 - Dialogue when collision detection occurs in Enhanced Manchester