TSS461E - Advance Information

Features
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Fully Compliant to VAN Specification ISO/11519.3
Handles All Specified Module Types
Handles All Specified Message Types
Handles Retransmission of Frames on Contention and Errors
3 Separate Line Inputs with Automatic Diagnosis and Selection
1 Mbit/s Maximum Transfer Rate
Normal or Pulsed (Optical and Radio Mode) Coding
Intel®, NEC®, Texas Instruments® and Motorola® Compatible 8-bit Microprocessor
Interface
Multiplexed Address and Data Bus
Idle and Sleep Modes
128 Bytes of General-purpose RAM
DMA Capabilities for Message Handling
14 Identifier Registers with All Bits Individually Maskable
6-source Maskable Interrupt Including an Interrupt-on-reset to Detect Glitches on the
Reset Pin
Integrated Crystal or Resonator Oscillator with Internal Baud Rate Generator and
Buffered Clock Output
Single +5V Power Supply
0.5 mm CMOS Technology
SOP 24 Packaging
Description
VAN Data Link
Controller
TSS461E
Advance
Information
Cost optimization in car manufacturing is of extreme importance today. Solutions to
this problem often implies the use of more advanced and intelligent electronic circuits.
The TSS461E is a circuit which allows the transfer of all the status information needed
in a car or truck over a single low-cost wire pair, thereby, minimizing the electrical wire
usage.
It can be used to interconnect powerful functions (ABS, dashboard, power train control) and to control and interface car body electronics (lights, wipers, power window,
etc.).
The TSS461E is fully compliant with the ISO standard 11519-3. This standard supports a wide range of applications such as low-cost remote control switches, typically
used for lamp control; complex, highly-autonomous, distributed systems like engine
controls, which require fast and secure data transfers.
The TSS461E is a microprocessor-interfaced line controller for mid-to-high complexity
bus-masters and listeners like injection/ignition control calculators, dashboard controllers and car stereo or mobile telephone CPUs.
The microprocessor interface consists of a 256-bytes of RAM and the register area is
divided into 11 control registers, 14 channel register sets and 128 bytes of general
purpose RAM, used as a message storage area, and a 6-source maskable interrupt.
The circuit operates in RAM using DMA techniques, controlled by the channel and
control registers. This allows virtually any microprocessor to interface with ease to the
TSS461E, and to use the free RAM as a scratch pad.
Messages are encoded in enhanced Manchester code, and an optional pulsed code
for use with an optical or radio link, at a maximum bit rate of 1 Mbit/s. The TSS461E
analyzes the messages received or transmitted according to 6 different criteria including some higher level checks.
In addition, the bus interface has three separate inputs with automatic source diagnosis and selection, allowing for multibus listening or the automatic selection of the most
reliable source at any time if several line receivers are connected to the same bus.
4194C–AUTO–01/06
Figure 1. Block Diagram
AD[7:0]
ALE
RESET TEST
INT
VCC GND
Address and Data Bus
Multiplexing logic
control bus
data bus
Status and
control
registers
address bus
status bus
128 bytes
Message
buffer
RAM
Protocol controller
state machine and
ID registers
Data serializer and
deserializer
Clock generator and
line synchronization
logic
XTAL1 XTAL2
2
CKOUT
Reception logic
Source diagnosis
and selection logic
CRC generator
and checker
Transmission logic
TxD
RxD0 RxD1 RxD2
TSS461E
4194C–AUTO–01/06
TSS461E
Pin Configuration
TOP VIEW
24 Pin SOP
AD4
1
24
AD3
AD5
2
23
AD2
AD6
3
22
AD1
AD7
4
21
AD0
VCC
5
20
VSS
INT
6
19
RESET
ALE
7
18
TXD
(E) CS
8
17
RXD0
XTAL1
9
16
RXD2
XTAL2
10
15
RXD1
TEST/VSS
11
14
WR (R/W)
CKOUT
12
13
RD (VSS)
The names in parenthesis refer to the functionalities in Motorola mode.
I/O Type
Pin Name
Pin Number
I/O TTL
AD0
21
AD1
22
AD2
23
AD3
24
AD4
1
AD5
2
AD6
3
AD7
4
ALE
7
Address Latch Enable
RD (VSS)
13
Read Command
WR (R/W)
14
Write Command
CS(E)
8
Chip Select (active high)
INT
6
Interrupt
RESET
19
Asynchronous general
reset glitch filtered
(12 ns)
I Trigger TTL
Open-drain
I Trigger CMOS Pull-down
Pin Function
Multiplexed address and
data bus. The address is
latched on the falling
address of ALE.
3
4194C–AUTO–01/06
I/O Type
Pin Name
Pin Number
RXD0
17
RXD1
15
RXD2
16
TXD
18
VAN bus Output
I
XTAL1
9
0
Crystal oscillator or clock
input pins
XTAL2
10
CKOUT
12
Buffered clockout output
enabled if no reset
Ground
TEST/VSS
11
Oscillator Ground
Power
VCC
5
+5V Power Supply
Ground
VSS
20
I CMOS Pull-down
3-state
0
4
Pin Function
VAN bus Inputs
TSS461E
4194C–AUTO–01/06
TSS461E
Operation
The TSS461E is a microprocessor-controlled line controller for the VAN bus. It can interface to
virtually any microprocessor, but the I/O signals of the circuit have been optimized for use with
the TSC51/TSC251 series of microcontrollers.
It features a multiplexed address and data bus, controlled by an address strobe pin ALE and
separated read RD and write WR command pins. The address is latched on the falling edge of
ALE.
The circuit also features one single interrupt pin. This pin can be treated as level or edge sensitive, For example, if there is a pending interrupt inside the circuit when another interrupt is reset,
the INT pin will emit a high pulse with the same pulse width as the internal write strobe (typically
20 ns).
Figure 2. Typical Application
VAN Bus
General I/O
Remaining Pins
GND
XTAL1
P3.6/WR
WR
P3.7/RD
RD
XTAL2
TXD
GND
Differential
DATA
33 pF
C1
DATA
TSS461E
Series
Microcontroller
+
RXD0
ALE
ALE
P0.7
P0.6
P0.5
P0.4
P0.3
P0.2
P0.1
P0.0
AD7
AD6
AD5
AD4
AD3
AD2
AD1
AD0
RESET XTAL1 INT
VCC
VAN
DLC
RXD1
RXD2
DATA
+
-
CS
INT CKOUT RESET
DATA
VREF
+
VAN Line Driver
& Receivers
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4194C–AUTO–01/06
Microprocessor
Interface
The processor controls the TSS461E by reading and writing the internal registers of the circuit.
These registers appear to the processor as regular memory locations.
Interface Modes
The TSS461E must be plugged in an Intel or Motorola environment with an 8-bit address/data
bus multiplexed.
Table 1. Access Mode Logic
CS (E)
RD
WR (R/W)
Operation Mode
No operation
0
1
0
0
Write Operation in Motorola mode
1
0
1
Read operation in both modes
1
1
0
Write operation in Intel mode
1
1
1
No operation
In Intel environment, access operations need CS active, a read one with RD active, a write one
with WR active. If TSS461E is the single peripheral in the processor space, CS can be wired to
VCC.
In Motorola environment, the RD pin is wired to VSS and the access operations are driven by
CS (E). Contrary to Intel mode, CS (E) must never be wired to Vcc even if the TSS461E is alone.
To switch on-the-fly from one mode to the other, CS must be inactive.
Intel Mode
The Intel mode interface consists of 13 pins. 8 pins are the multiplexed address and data bus,
and the rest are the address strobe, the read and write commands, the chip select and the interrupt request pins.
To access the memory locations in Intel mode, the processor must first assert a valid address on
the multiplexed address and data bus and drive the address strobe pin high. When the required
set up time has passed, the processor must drive the address strobe low, and keep the address
valid for the required hold time.
The processor must then either assert the data to be written on the address and data bus, if a
write is intended, or float the data bus for a read. The next step is to drive either the write or read
command pins low, according to the function required, and at the same time drive the chip select
pin high.
The TSS461E access cycle is then terminated by driving the chip select and command pins low.
Note:
6
that the chip select pin may be driven high for the entire access cycle, and may also remain high
during and after the termination of the cycle.
TSS461E
4194C–AUTO–01/06
TSS461E
Figure 3. Intel Read and Write Cycles
ALE
AD[7:0]
ADDRESS
DATA TO BE
WRITTEN
ADDRESS
DATA
READ
RD
WR
CS
WRITE CYCLE
Motorola Mode
READ CYCLE
In Motorola mode, the WR pin becomes the R/W command, the RD pin must be connected to
ground and the CS pin becomes the E strobe. There is no separate chip select input. For example, if some external decoder is used, this decoder should not drive the E input high unless the
processors E output is high as well.
See Figure 4 for the Motorola read and write cycles. The main difference between Intel and
Motorola mode is that the timing in Intel mode is referenced to the command signals (RD and
WR), but in Motorola mode the reference is the E signal.
Figure 4. Motorola Read and Write Cycles
ALE
AD[7:0]
ADDRESS
DATA TO BE
WRITTEN
ADDRESS
DATA
READ
VSS (RD)
R/W (WR)
E (CS)
WRITE CYCLE
Interrupts
READ CYCLE
If an event occurs in the TSS461E, that needs the attention of the processor, this will be signalled on the active low, open-drain interrupt request pin. The events that create this request is
controlled by the internal registers.
Every time the microprocessor accesses any of the interrupt registers (addresses 0x08 to 0x0B),
the INT pin will be released momentarily. This enables the TSS461E to work with processors
that have either edge or level sensitive interrupt inputs.
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4194C–AUTO–01/06
Reset
The reset is applied asynchronously regarding XTAL clock. It can be done either by the RESET
pin or by software. The RESET pin is a CMOS trigger input with a pull-down resistor (110 kΩ).
An external 1 µF capacitor to VCC provides to RESET pin an efficient behavior.
The software reset is made through the GRES command bit of the Command Register (0x03).
The two resets are ored, filtered and gauged. T
he internal reset, always asserted asynchronously, enables the internal oscillator. Then it waits
for eight clock periods the oscillator stability.
The different blocks of the TSS461E need to be turned on synchronously. So the release of the
internal reset is synchronous and a loose of clock can let the TSS461E in permanent reset after
applying Reset.
8
TSS461E
4194C–AUTO–01/06
TSS461E
Oscillator
An oscillator is integrated in the TSS461E, and consists of an inverting amplifier which the input
is XTAL1 and the output XTAL2.
A parallel resonance quartz crystal or ceramic resonator must be connected to these pins. As
shown in Figure 2, two capacitors have to be connected from the crystal pins to ground. The values of C1 depend on the frequency chosen and can be selected using the graphic given in
Figure 34.
If the oscillator is not used, then a clock signal must be fed to the circuit via the XTAL1 input.
Note, that this pin will behave as a CMOS level compatible Schmitt trigger input.
In this case, the XTAL2 output should be left unconnected. The oscillator also features a buffered clock output pin CKOUT. The signal on this pin is directly buffered from the XTAL1 input,
without inversion.
There is one more pin used for the oscillator. The TEST/VSS pin is in fact its ground, and unless
this pin is firmly connected to ground, with decoupling capacitors, the oscillator will not operate
correctly.
The test mode itself, i.e., when the TEST/VSS pin is held high, is only intended for factory use,
and the functionality of this mode is not specified in any way.
Furthermore, it is subject to change without notice, the only exception being for incoming inspection tests using the test program.
The clock signal is then fed to the clock generator generate all the necessary timing signals for
the operation of the circuit. The clock generator is controlled by a 4-bit code called the clock
divider.
F XTAL1
F TSCLK = -----------------n × 16
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4194C–AUTO–01/06
Table 2. Clock Divider
8 MHz
10
6 MHz
4 MHz
2 MHz
Clock
Divider
Divide by
KTS/s
Kbits/s
KTS/s
Kbits/s
KTS/s
Kbits/s
KTS/s
Kbits/s
0000
1
500
400
375
300
250
200
125
100
0001
2
250
200
187.50
150
125
100
62.50
50
0010
4
125
100
93.75
75
62.50
50
31.25
25
0011
8
62.5
50
46.875+
37.5
31.25
25
15.625
12.5
0100
16
31.25
25
23.438
18.75
15.625
12.5
7.813
6.25
0101
32
15.625
12.5
11.718
9.375
7.813
6.25
3.906
3.125
0110
64
7.813
6.25
5.859
4.688
3.906
3.125
1.953
1.562
0111
128
3.906
3.125
500
400
1.953
1.562
166.666
133.333
1000
1.5
333.333
266.666
250
200
166.666
133.333
83.333
66.666
1001
3
166.666
133.333
125
100
83.333
66.666
41.666
33.333
1010
6
83.333
66.666
62.50
50
41.666
33.333
20.833
16.666
1011
12
41.666
33.333
31.25
25
20.833
16.666
10.416
8.333
1100
24
20.833
16.666
15.625
12.50
10.416
8.333
5.208
4.166
1101
48
10.416
8.333
7.813
6.25
5.208
4.166
2.604
2.083
1110
96
5.208
4.166
3.906
3.125
2.604
2.083
1.302
1.042
1111
192
2.604
2.083
1.953
1.5625
1.302
1.042
0.651
0.521
TSS461E
4194C–AUTO–01/06
TSS461E
VAN Protocol
Line Interface
There are three line inputs and one line output available on the TSS461E. Each of the three
inputs to use is either programmed by software or automatically selected by a diagnosis system.
The diagnosis system continuously monitors the data received through the three inputs, and
compares them and the selected bitrate. It then chooses the most reliable input according to the
results.
The data on the line is encoded according to the VAN standard ISO/11519-3. This means that
the TSS461E is using a two-level signal having a recessive (1) and a dominant (0) state. Furthermore, due to the simple medium used, all data transmitted on the bus is also received
simultaneously.
Consequently, the VAN protocol is a CSMA/CD (Carrier Sense Multiple Access/Collision Detection) protocol, allowing for continuous bitwise arbitration of the bus, and non-destructive (for the
higher priority message) collision detection.
Figure 5. CSMA/CD Arbitration
Arbitration field
Node a: TxD
R
D
Node b: TxD
R
D
Node c: TxD
R
D
On Bus: DATA
2
Node a loses the arbitration
Node a releases the bus
3
1
Node b wins the arbitration
Node c loses the arbitration
Node c releases the bus
R
D
R: Recessive level
D: Dominant level
In addition to the VAN specification there is also a pulsed coding of the dominant and recessive
states. This mode is intended to be used with an optical or radio link. In this mode, the dominant
state for the transmitter is a low pulse, (2x prescaled clocks at the beginning of the bit) and the
recessive state is just a high level.
When receiving in this mode, it is not the state of the signal which is decoded, but the edges.
Also, reception is imposed on the RxD0 input, and the diagnosis system does not operate
correctly.
In addition, in this mode there is an internal loopback in the circuit since optical transceivers are
not able to receive the signal that they transmit.
11
4194C–AUTO–01/06
Figure 6. State Encoding
VAN BUS
SEQUENCE
NORMAL OR PULSED RECESSIVE STATE
VAN BUS
SEQUENCE
NORMAL DOMINANT STATE
VAN BUS
SEQUENCE
PUSED DOMINANT STATE
NUMBER OF
PRESCALED
CLOCKS
0
2
4
6
8
10
12
14
16
In Figure 6 the pulsed waveforms are shown. In Figure 9 through Figure 15 the low "timeslots"
(i.e. blocks of 16 prescaled clocks) should be replaced by the dominant waveform showed in
Figure 6, if the correct representations for pulsed coding is desired.
VAN Frame
Figure 7. VAN Bus Frame
SOF
Identifier
Field
Command
EXT
RAK
R/W
Data
Field
RTR
Frame
Check
Sum
EOD
ACK
EOF
The VAN bus supports three different module (unit) types:
1. The Autonomous module, which is a bus master. It can transmit Start Of Frame (SOF)
sequences, it can initiate data transfers and can receive messages.
2. The Synchronous access module. It cannot transmit SOF sequences, but it can initiate
data transfers and can receive messages.
3. The Slave module, which can only transmit using an in-frame mechanism and can
receive messages.
Figure 8. Hierarchical Access Methods
Autonomous
Rank 0
SOF
ID
COM
DATA
FCS
EOD ACK
EOF
COM
DATA
FCS
EOD ACK
EOF
DATA
FCS
EOD ACK
EOF
Rank 1
Rank 16
12
ID
RTR
Synchronous
Slave
TSS461E
4194C–AUTO–01/06
TSS461E
Figure 7 shows a normal VAN bus frame. It is initiated with a Start of Frame (SOF) sequence
shown in Figure 9. The SOF can only be transmitted by an autonomous module. During the preamble, the TSS461E will synchronize its bit rate clock to the data received.
Figure 9. Framing Sequences
VAN BUS
START
SYNC
PREAMBLE
SEQUENCE
START OF FRAME
VAN BUS
END OF
DATA
ACK
SEQUENCE
NUMBER OF
PRESCALED
CLOCKS
0
16
32
48
END OF FRAME
64
80
96
112 128 144
160 176 192
When the complete SOF sequence has been transmitted or received, the circuit will start the
transmission or reception of the identifier field.
All data on the VAN bus, including the identifier and Frame Check Sum (FCS), are transmitted
using enhanced Manchester code.
In enhanced Manchester code, three NRZ bits are transmitted first followed by one Manchester
bit, then three more NRZ bits followed by one Manchester bit and so on.
Since the high state is recessive and the low state is dominant, the bus arbitration can be done.
If a module wants access to the bus, it must first listen to the bus during one full End of Frame
(EOF) and one full Inter Frame Spacing (IFS) period, to determine whether the bus is free or not
(i.e.,no dominant states received).
Figure 10. Data Encoding
VAN BUS
SEQUENCE
NRZ 0
VAN BUS
SEQUENCE
NRZ 1
MANCHESTER 0
VAN BUS
SEQUENCE
MANCHESTER 1
NUMBER OF
PRESCALED
CLOCKS
0
8
16
24
32
The IFS is defined to be a minimum of 64 prescaled clocks periods. The TSS461E, accepts an
IFS of zero prescaled clocks for the reception only of a SOF sequence.
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4194C–AUTO–01/06
Once the bus is free, the module must now, if it is an autonomous module emits a SOF
sequence or, if it is a synchronous access module, wait until it detects a preamble sequence.
Up till this point there can be several modules transmitting on the bus, and there is no possibility
of knowing if this is the case or not. Therefore, the first field in which arbitration can be performed is the identifier field. Since the logical zeroes on the bus are dominant, and all data is
transmitted with the most significant bit (MSB) first, the first module to transmit a logical zero on
the bus will be the prioritized module, i.e., the message that is tagged with the lowest identifier
will have priority over the other messages.
However it is possible that two messages transmitted on the bus will have the same identifier.
The TSS461E therefore, continues the arbitration of the bus throughout the whole frame. In
addition, if the identifier in transmission has been programmed for reception as well, it transmits
and receives messages simultaneously, right up till the Frame Check Sequence (FCS). Only
then, if the TSS461E has transmitted the whole message. It discards the message received.
Arbitration loss in the FCS field is considered as a CRC error during transmission.
This feature is called full data field arbitration, and it enables the user to extend the identifier. For
instance, it can be used to transmit the emitting modules address in the first bytes of the data
field, thus enabling the identifier to specify the contents of the frame and the data field to specify
the source of the information.
The identifier field of the VAN bus frame is always 12 bits long, and it is always followed by the
4-bit command field:
•
The first bit of the command is the extension bit (EXT). This bit is defined by the user on
transmission and is received and retained by the TSS461E. To conform with the standard, it
should be set to 1 (recessive) by the user, else the frame is ignored without any IT
generation.
•
The second bit is the request ACKnowledge bit (RAK). If this bit is a logical one, the
receiving module must acknowledge the transfer with an in-frame acknowledgement in the
ACK field. If it is set to logical zero, then the ACK field must contain an acknowledge absent
sequence.
•
The third bit is the Read/Write bit (R/W). This bit indicates the direction of the data in a
frame.
•
If set to zero it is a "write" message, i.e. data transmitted by one module to be received by
another module. If it is set to one it implies a "read" message, i.e., a request that another
module should transmit data to be received by the one that requested the data (reply
request message).
•
Last in the command field is the Remote Transmission Request bit (RTR). This bit is a
logical zero if the frame contains data and a logical one if the frame does not contain data. In
order to conform with the standard a received frame included the combination R/W. RTR =
01 is ignored without any IT generation.
All the bits in the command field are automatically handled by the TSS461E, so the user doesn’t
need to be concerned for the encoding and decoding of these. The command bits transmitted on
the VAN bus are calculated from the current status of the active message.
After the command field comes the data field. This is just a sequence of bytes transmitted, MSB
first. In the VAN standard the maximum message length is set to 28 bytes, but the TSS461E
handles messages up to 30 bytes.
The next field is the FCS field. This field is a 15 bit CRC checksum defined by the following generator polynomial g(x) of order 15:
g(x) = x15 + x11 + x10 + x9 + x8 + x7 + x4 + x3 + x2 + 1
14
TSS461E
4194C–AUTO–01/06
TSS461E
The division is done with a rest initialized to 0x7FFF, and an inversion of the CRC bits is performed before transmission.
However, since the CRC is calculated automatically from the identifier, command and data fields
by the TSS461E, the user should not be concerned with the circuit. When the frame check
sequence has been transmitted, the transmitting module must transmit an End Of Data (EOD)
sequence, followed by the ACKnowledge field (ACK) and the End of Frame sequence (EOF) to
terminate the transfer.
Figure 11. Acknowledge Sequences
VAN BUS
SEQUENCE
POSITIVE ACKNOWLEDGE
VAN BUS
SEQUENCE
NUMBER OF
PRESCALED
CLOCKS
Frame Examples
ABSENT ACKNOWLEDGE
0
8
16
24
32
The frames transmitted on the VAN bus are generated by several modules, each supplying different parts of the message. Figure 12 through Figure 15 show the four frame types specified in
the VAN standard, and what module is generating the different fields.
•
The most straightforward frame is the normal data frame in Figure 13. Like all other frames it
is initiated with a SOF sequence. This sequence is generated by a bus master (not shown in
figure).
•
During this frame, there is basically only one module transmitting with the exception being
the acknowledgement, generated by the receiving module if requested in the RAK bit.
•
The reply request frame with immediate reply in Figure 13 is the only frame in which a slave
module can transmit data by filling it into the appropriate field.
•
The difference for the frame on the bus is that the R/W bit has changed state compared to
the normal frame.
•
This is a highly interactive frame where a bus master generates the SOF and the initiator
generates the identifier, the three first bits of the command, and the acknowledge. The RTR
bit, the data field, the frame check, the EOD and the EOF are all generated by the replying
module.
•
The reply request frame with deferred reply in Figure 14 is the same frame as the reply
request frame with immediate reply. But since the requested module does not generate the
RTR bit, the requesting module will continue with the frame check, the EOD and the EOF.
•
During this frame, the requested module will only generate the acknowledge, and only if this
was requested by the initiator through the RAK bit.
•
Finally, the deferred reply frame in Figure 16 which is sent when a module has prepared a
reply for a reply request that has been received earlier.
This frame is similar to the normal data frame with the exception being the R/W bit that has
changed state.
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4194C–AUTO–01/06
Figure 12. Normal Data Frame
EOD
ACK
DATA
CRC
EOD
ACK
EOF
CRC
ACK
EOF
CRC
EOF
RECEIVING
module
FRAME
on bus
EOF
ACK
IDENTIFIER
CRC
EOD
SOF
DATA
ACK
IDENTIFIER
EOD
SOF
EXT
RAK
R/W
RTR
(*)
TRANSMITTING
module
EXT
RAK
R/W
RTR
(*)
With acknowlegment
EXT :
RAK :
R/W :
RTR :
ACK :
Recessive from ransmitter
T
Recessive for acknowledge from
ransmitter
T
Dominant from T
ransmitter
Dominant from T
ransmitter(*) Manchester bit
Positive from Receiver because RAK is Recessive
SOF
IDENTIFIER
EXT
RAK
R/W
RTR
(*)
TRANSMITTING
module
DATA
SOF
IDENTIFIER
EXT
RAK
R/W
RTR
(*)
Without acknowlegment
DATA
RECEIVING
module
FRAME
on bus
T
EXT : Recessive from ransmitter
RAK : Dominant for no acknowledge fromransmitter
T
R/W : Dominant from T
ransmitter
ransmitter(*) Manchester bit
RTR : Dominant from T
ACK : Absentfrom Transmitter and from Receiver because RAK is Dominant
16
TSS461E
4194C–AUTO–01/06
TSS461E
CRC
EOD
ACK
EOF
DATA
CRC
ACK
EOF
REQUESTED
module
FRAME
on bus
SOF
EXT
RAK
R/W
RTR
ACK
:
:
:
:
:
IDENTIFIER
ACK
DATA
EOD
IDENTIFIER
RTR
(*)
SOF
EXT
RAK
R/W
RTR
(*)
REQUESTING
module
EXT
RAK
R/W
RTR
(*)
Figure 13. Reply Request Frame with Immediate Reply
Recessive from Requestor
Recessive for acknowledge from Requestor
Recessive from Requestor
Recessive from Requestor and Dominant from Requestee
(*) Manchester bit
Absent from Requestee and Positive from Requestor because RAK is Recessive
ACK
CRC
REQUESTED
Module
FRAME
on Bus
EOF
ACK
IDENTIFIER
ACK
SOF
CRC
EOD
IDENTIFIER
EOD
SOF
EXT
RAK
R/W
RTR
(*)
REQUESTING
Module
EXT
RAK
R/W
RTR
(*)
Figure 14. Reply Request Frame with Deferred Reply
EOF
EXT : Recessive from Requestor
RAK : Recessive for acknowledge from Requestor
R/W : Recessive from Requestor
RTR : Recessive from Requestor - (*) Manchester bit
ACK : Absent from Requestor and Positive from Requestee because RAK is Recessive
17
4194C–AUTO–01/06
ACK
DATA
CRC
EOF
ACK
IDENTIFIER
CRC
EOD
SOF
DATA
ACK
IDENTIFIER
EOD
SOF
EXT
RAK
R/W
RTR
(*)
REPLYING
module
EXT
RAK
R/W
RTR
(*)
Figure 15. Deferred Reply Frame
RECEIVING
module
FRAME
EOF
on bus
EXT
RAK
R/W
RTR
ACK
18
:
:
:
:
:
Recessive from Replyer
Recessive for acknowledge from Replyer
Recessive from Replyer
(*) Manchester bit
Dominant from Replyer
Absent from Replyer and Positive from Receiver because RAK is Recessive
TSS461E
4194C–AUTO–01/06
TSS461E
Diagnosis
System
The purpose of the diagnosis system is to detect any short or open circuits on either the DATA
or DATA lines and to permit, if it is possible, to carry the communications on the non-defective
line.
The diagnosis system is based on the assumption that three separate line receivers are connected to the VAN bus (see Figure 3):
•
One of the line receivers is connected in differential mode, sensing both DATA and DATA
signals, and is connected to the RxD0 input.
•
The other two line receivers are operating in single wire mode and are sensing only one of
the two VAN bus signals:
–
The line receiver sensing DATA is connected to RxD1
–
The line receiver sensing DATA is connected to RxD2
The diagnosis system analyzes and compares the data sent over both VAN lines. So, the diagnosis system executes a digital filtering and transition analyses. In order to perform its
investigation, three internal signals are generated, RI (Return to Idle), SDC (Synchronous Diagnosis Clock) and TIP (Transmission In Progress).
One of four operating modes can be chosen to manage the results of the diagnosis system.
Diagnosis States
If the diagnosis system finds a failure on either of the VAN bus signals, it changes from nominal
to degraded mode, and connects the line receiver not coupled to the failing signal to the reception logic.
When the diagnosis system finds that the failing signal is working again, it returns to nominal
mode and re-connects the differential line receiver to the reception logic.
A major error occurs when both the VAN bus signals fail.
Figure 16. Diagnosis States
NONIMAL
MAJOR
ERROR
DEGRATED
DATA
DEGRATED
DATA
- Failure during the frame.
- Default of transitions on the valid input between 2 consecutive SDC rising edges.
- Protocol fault
- In specified selection mode, every RI pulse when an EOF is detected or through an active SDC.
- In automatic selection mode and SDC active, no failure sampled by 2 consecutive SDC rising edges.
- General reset
Status bits give permanent information on the diagnosis performed, whatever the programmed
operating mode. This is encoded over three bits: Sa, Sb and Sc. Sa and Sb bits indicate the four
possible states of the VAN bus.
19
4194C–AUTO–01/06
Table 3. Status Bits Sa and Sb
Sa
Sb
0
0
0
1
1
Notes:
1
0
1
Communication
Mode
nominal
Fault
no fault on VAN bus
Status
differential communication DATA and DATA
Mode
degraded on DATA
Fault
fault on DATA
Status
communication on DATA
Mode
degraded on DATA
Fault
fault on DATA
Status
communication on DATA
Mode
major error
Fault
fault on DATA and DATA
Status
no communication on DATA and DATA (attempt to
communicate alternatively on DATA then DATA every
SDC period.
1. Sc bit sets to 1 as soon as one of the three inputs (RXD2, RXD1, RXD0) differs from the others
in the input comparison analysis performed by the diagnosis system, S2 is set.
2. The only way to reset this status bit is through the RI signal or a general reset.
Internal
Operations
Digital Filtering
If several spurious pulses occur during one bit, the diagnosis for defective conductor may be
corrupted. To avoid such errors, digital filters are implemented.
Filtering operation is based on sampling of the comparator output signals. A transition is taken
into account only if it is observed over five samples (1/16th of timeslot).
Transition Analyses
20
These analyses are continuously done on the effective edges on comparators after digital
filtering.
•
Asynchronous diagnosis:
The asynchronous diagnosis is done by comparing the number of edges on DATA and
DATA.
If four edges are detected on one input and no edges on the other during the same period,
the second input is considered faulty and the diagnosis mode will change to one of the
degraded modes.
•
Synchronous diagnosis:
The synchronous diagnosis counts the number of edges on the data input connected to the
reception logic during one SDC period.
If there are less than four edges during one SDC period, the diagnosis mode will change to
the major error mode.
•
Transmission diagnosis:
The transmission compares RxD1 and RxD2 inputs (through the input comparators and the
TSS461E
4194C–AUTO–01/06
TSS461E
filters) with the data transmitted on TxD output.
At a time when the transmission logic generates a dominant (recessive transition), the inputs
can give different values. Taking into account the filtering delay, the bus line seen as
dominant is assumed to be correct, the other one, recessive, is considered faulty. The
diagnosis mode is changed to reflect that.
•
Protocol fault:
The protocol fault is detected by counting the number of consecutive dominant timeslots.
If eight consecutive timeslots are dominant, the diagnosis mode will change to the major
error mode.
Generation of
Internal Signals
RI Signal (Return to
Idle)
This signal is used to return to nominal mode in the three specified selection modes (see
section “Diagnosis States” and section “Programming Modes”). The RI signal is disabled in automatic selection mode.
The RI signal is a pulse generated when an EOF is detected. So, at the end of each frame, the
user, regarding the diagnosis status bit Sa, Sb & Sc, can select its own choice.
SDC Signal
(Synchronous
Diagnosis Clock)
This time base is used by diagnosis system in automatic selection mode (see
section “Programming Modes”) when no event is recorded on the bus.
The SDC is generated either by a special SDC divider connected to the timeslot clock, or manually. The SDC clock period must be longer compared to the timeslot duration.
A typical SDC period should be greater than the maximum frame length appearing on the VAN
network.
TIP Signal
(Transmission In
Progress)
This signal must be enabled to allow the transmission diagnosis (see section “Transition
Analyses”).
The TIP turns on synchronously at the beginning of the transmission:
•
For asynchronous bus access, the beginning of SOF,
•
For synchronous bus access, the beginning of the identifier field,
•
For a request of in frame reply, the RTR bit of the command field.
The TIP turns off synchronously at the end of the transmission:
•
after EOF
•
after a losing of arbitration or a code violation detection
•
for a requester of in frame reply, when the arbitration is lost on RTR the bit.
This signal is not generated when the transmission logic only sends an ACK.
21
4194C–AUTO–01/06
Programming
Modes
Four programming modes determine the way for using three different inputs and the diagnosis
system.
•
3 specified selection modes
•
1 automatic selection mode
Table 4. Programming Modes
22
Ma
Mb
Operating Mode
0
0
Differential communication
0
1
Degraded communication on RxD2 (DATA)
1
0
Degraded communication on RxD1 (DATA)
1
1
Automatic selection according to the diagnosis status
TSS461E
4194C–AUTO–01/06
TSS461E
Registers
The TSS461E memory map consists of three different areas, the Control & Status registers, the
Channel Registers and the Message Data (or Mailbox).
Mapping
Figure 17. Memory Map
0x78 to 0x7F (r/w)
Channel
13
Channel 13
0x70 to 0x77 (r/w)
Channel 12
0x68 to 0x6F (r/w)
Channel 11
0x60 to 0x67 (r/w)
Channel 10
0x58 to 0x5F (r/w)
Channel 9
0x50 to 0x57 (r/w)
Channel 8
0x48 to 0x4F (r/w)
Channel 7
0x40 to 0x47 (r/w)
Channel 6
0x38 to 0x3F (r/w)
Channel 5
0x30 to 0x37 (r/w)
Channel 4
0x28 to 0x2F (r/w)
Channel 3
0x20 to 0x27 (r/w)
Channel 2
0x18 to 0x1F (r/w)
Channel 1
0x10 to 0x17 (r/w)
Channel 0
0x0C to 0x0F
Reserved
Interrupt Reset
0x0B (w)
0x0A (r/w) Interrupt Enable (0x80)
Interrupt Status (0x80)
0x09 (r)
Reserved
0x08
Last
Error
Status (0x00)
0x07 (r)
Last
Message
Status (0x00)
0x06 (r)
Transmit
Status
(0x00)
0x05 (r)
Line
Status
(0bx01xxx00)
0x04 (r)
Command (0x00)
0x03 (w)
Diagnosis
Control (0x00)
0x02 (r/w)
Transmit
Control
(0x02)
0x01 (r/w)
Line
Control
(0x00)
0x00 (r/w)
Register
Notes:
Data Byte 127
0xFF
0x7F (r/w)
0x7E (r/w)
ID_Mask [3..0]
ID_Mask [11..4]
0x7C & 0x7D
Reserved
Reserved
0x7B (r/w) Message Length + Status
0x7A (r/w) DRAK + Message Address
0x79 (r/w) ID_TAG (lsb) + COM
ID_TAG (msb)
0x78 (r/w)
Channel 13 Registers
0x17 (r/w)
0x17 (r/w)
ID_Mask [3..0]
ID_Mask [11..4]
ID_Mask
[11..4]
0x16 (r/w)
Reserved
0x14 & 0x15
0x13 (r/w) Message Length + Status
0x12 (r/w) DRAK + Message Address
0x11 (r/w) ID_TAG [3..0] + COM
0x10 (r/w)
ID_TAG [11..4]
Channel 0 Registers
0x8C
0x8B
0x8A
0x89
0x88
0x87
0x86
0x85
Data Byte 12
Data Byte 11
Data Byte 10
Data Byte 9
Data Byte 8
Data Byte 7
Data Byte 6
Data Byte 5
0x84
0x83
0x82
0x81
0x80
Data Byte 4
Data Byte 3
Data Byte 2
Data Byte 1
Data Byte 0
Message
1. All the non-specified addresses between 0x00 and 0x7F are considered as absent.
2. (r) means read only register.
(w) means write only register.
(r/w) means read/write register.
3. Value after RESET is found after register name. If no value is given, the register is not initialized at RESET.
23
4194C–AUTO–01/06
Control and Status Registers
Line Control Register
(0x00)
CD[3:0] Clock Divider
7
6
5
4
3
2
1
0
MR3
MR2
MR1
MR0
VER2
VER1
VER0
MT
•
Read/write register.
•
Default value after reset: 0y00
•
reserved: Bit 2, this bit cannot be set by the user; a 0 must always be written to this bit.
They control the VAN Bus rate through a Baud Rate generator according to the formula below:
F XTAL1
F TSCLK = -----------------n × 16
PC Pulsed CodeOne
The TSS461E will transmit and receive data using the pulsed coding mode (i.e optical or radio
link mode). The use of this mode implies communication via the RXD0 input and the non-functionality of the diagnosis system.
Zero: (default at reset) The TSS461E will transmit and receive data using the Enhanced
Manchester code (RXD0, RXD1, RXD2).
IVTX
Invert TXD output.
IVRX
Invert RXD inputs.The user can invert the logical levels used on either the TXD output or the
RXD inputs in order to adapt to different line drivers and receivers.
One: A one on either of these bits will invert the respective signals.
Zero: (default at reset). The TSS461E will set TXD to recessive state in Idle mode and consider
the bus free (recessive states on RXD inputs).
Transmit Control
Register (0x01)
24
7
6
5
4
3
2
1
0
MR3
MR2
MR1
MR0
VER2
VER1
VER0
MT
•
Read/Write register
•
Default value after reset: 0x02
TSS461E
4194C–AUTO–01/06
TSS461E
MR[3:0]: Maximum
Retries
These bits allow the user to control the amount of retries the circuit will perform if any errors
occurred during transmission.
Table 5. Retries
Note:
VER[2:0]: DLC Version
After Reset
MR [3:0]
Max Number of Retries
Max Number of Transmits
0000
0
1
0001
1
2
0010
2
3
0011
3
4
0100
4
5
0101
5
6
0110
6
7
0111
7
8
1000
8
9
1001
9
10
1010
10
11
1011
11
12
1100
12
13
1101
13
14
1110
14
15
1111
15
16+
Bus contention is not regarded as an error and that an infinite number of transmission attempts
will be performed if bus contention occurs continuously.
•
000: TSS461A & B
•
001: TSS461C and TSS461E
These bits cannot be set by user; 001 must always be written to these bits.
MT: Module Type
The three different module types are supported (see section “VAN Frame”):
One: The TSS461E is an autonomous module (Rank 0), an synchronous access module (Rank
1) or a slave module (Rank 16).
Zero: The TSS461E is an synchronous access module (Rank 1) or a slave module (Rank 16).
25
4194C–AUTO–01/06
Diagnosis Control
Register (0x02)
7
6
5
4
3
2
1
0
SDC3
SDC2
SDC1
SDC0
Ma
Mb
ETIP
ESDC
•
Read/Write register
•
Default value after reset: 0x00.
The diagnosis is discussed in detail in section “Diagnosis States”.
SDC [3:0]: SDC divider
•
In its four high order bits the user can program the SDC rate SDC [3:0]
•
In its two medium order bits the diagnosis system mode is controlled: M1, M0
•
In the two low order bits, the user controls if the SDC and TIP are to be generated
automatically ETIP, ESDC
The input clock is the times lot clock.
Table 6. System Diagnosis Clock Divider
26
SDC Divider SDC [3:0]
Divide By
0000
64
0001
128
0010
256
0011
512
0100
1024
0101
2048
0110
4096
0111
8192
1000
16384
1001
32768
1010
65536
1011
131072
1100
262144
1101
524288
1110
1048576
1111
2097152
TSS461E
4194C–AUTO–01/06
TSS461E
Ma, Mb: Operating
mode command bits
Table 7. Diagnosis System Command Bits
Ma
Mb
0
0
Forces the Communication on RxD0 (differential)
0
1
Forces the Communication on RxD2 (DATA)
1
0
Forces the Communication on RxD1 (DATA)
1
1
Automatic selection
ETIP: Enable
Transmission In
Progress
One: Enable TIP generation
ESDC: Enable System
Diagnosis Clock
One: Enable SDC divider.
Zero: Disable TIP generation.
•
The Transmission In Progress (TIP) tells the diagnostic system to enable transmission
diagnosis.
Zero: Disable SDC divider.
-The Synchronous Diagnosis Clock (SDC) controls the cycle time of the synchronous diagnosis.
Command Register
(0x03)
GRES: General Reset
7
6
5
4
3
2
1
0
GRES
SLEEP
IDLE
ACTI
REAR
0
0
MSDC
•
Write only register.
•
Reserved: Bit 1, 2 these bit cannot be set by the user; a zero must always be written to
these bit.
•
If the circuit is operating at low bit rates there might be a considerable delay between the
writing of this register and the performing of the actual command (worst case 6 timeslots).
The user must verify, by reading the Line Status Register (0x04) that the commands have
been performed.
The Reset circuit command bit performs, if set, exactly as if the external reset pin was asserted.
This command bit has its own auto-reset circuitry.
One: Reset active
Zero: Reset inactive
SLEEP: Sleep
Command
If the user sets the Sleep bit, the circuit will enter sleep mode. When the circuit is in sleep mode,
all non-user registers are setup to minimize power consumption and the oscillator is stopped. To
exit from this mode, the user must set either the idle or activate commands.
One: Sleep active
Zero: Sleep inactive
27
4194C–AUTO–01/06
IDLE: Idle Command
If the user sets the Idle bit, the circuit will enter idle mode. In idle mode the oscillator will operate, but the TSS461E will not transmit or receive anything on the bus, and the TXD output will
be in three-state
One: Idle active
Zero: Idle inactive
ACTI: Activate
Command
The Activate command will put the circuit in the active mode, i.e it will transmit and receive normally on the bus. When the circuit is in activate mode the TXD three-state output is enabled.
One: Activate active
Zero: Activate inactive
REAR: Re-Arbitrate
Command
This command will, after the current attempt, reset the retry counter and re-arbitrate the messages to be transmitted in order to find the highest priority message to transmit.
One: Re-arbitrate active
Zero: Re-arbitrate inactive
MSDC: Manual System
Diagnosis Clock
Rather than using the SDC divider described in section “Diagnosis Control Register (0x02)”, the
user can use the manual SDC command to generate a SDC pulse for the diagnosis system.
This MSDC pulse should be high at least two timeslot clock.
Line Status Register
(0x04)
7
6
5
4
3
2
1
0
x
SPG
IDG
Sc
Sb
Sa
TXG
RXG
Read only register.
•
Default value after reset: 0bx01xxx00.
•
This register reports the operation mode of the TSS461E in the Sleep an Idle bits
(Command Register located at address 0y03) as well as the diagnosis system status bits S2
to S0 discussed in section “Diagnosis System”.
SPG: Sleeping
IDG: Idling
Default mode at reset
Sa, Sb and Sc
Diagnosis system status bits
•
28
Sa and Sb
TSS461E
4194C–AUTO–01/06
TSS461E
Table 8. Diagnosis System Status Bits
•
Sb
Sa
Communication Indication
0
0
Nominal mode, differential communication
0
1
Degraded over DATA, fault on DATA
1
0
Degraded over DATA, fault on DATA
1
1
Major error, fault on DATA and DATA
Sc: As soon as one of the three inputs (RXD2, RXD1, RXD0) differs from the others in the
input comparison analysis perform by the diagnosis system, S2 is set.
The only way to reset this status bit is through the RI signal or a general reset.
TXG: Transmitting
If this status bit is active, it indicates that the TSS461E has chosen an identifier to transmit, and
it will continue to make transmission attempts for this message until it succeeds or the retry
count is exceeded.
RXG: Receiving
The receiving indicates that there is activity on the bus.
Note:
For safe modification of active channel registers both bits should be inactive (except "abort"
command).
Transmission Status Register (0x05)
7
6
5
4
3
2
1
0
NRT3
NRT2
NRT1
NRT0
IDT3
IDT2
IDT1
IDT0
•
Read only register.
•
Default value after reset: 0x00.
•
The transmission Status register contains the number of retries made up-to-date, according
to Table 3, and the channel currently in transmission.
NRT [3:0]: Number of
Retries Done in
Transmission
IDT [3:0]: Channel
Number Currently in
Transmission
Last Message Status Register (0x06)
7
6
5
4
3
2
1
0
NRTR3
NRTR2
NRTR1
NRTR0
IDTR3
IDTR2
IDTR1
IDTR0
•
Read only register.
•
Default value after reset: 0x00.
•
This register is the same as the transmission status register. It contains the last identifier
number that was successfully transmitted, received or exceeded its retry count.
If it was a successful transmission, the number of retries performed can be seen in this
register as well.
29
4194C–AUTO–01/06
NRTR [3:0]:
Number of retries done successfully in transmission. In case of reception NRTR[3:0] is
undefined.
IDTR [3:0]:
Channel number that was successfully transmitted, received or exceeded its retry count.
Last Error Status Register (0x07)
BOC: Buffer Occupied
BOV: Buffer Overflow
7
6
5
4
3
2
1
0
x
BOC
BOV
x
FCSE
ACKE
CV
FV
•
Read only register.
•
Default value after reset: 0×00.
•
The Last Error Status Register contains the error code for the last transmission or reception
attempt. It is updated after each attempt, i.e. several error codes can be reported during one
single transmission (with several retries).
•
When one channel configured in “Reply request” mode has its “received” bit set when it
attempts to transmit its request.
•
BOC with the link capability between two channels sharing the same received buffer is set
when one channel has already set its “received” bit in its “Message length and status
Channel register” and a receive is attempted on the other one.
BOV indicates that the buffer length setup in the Channel Status Register was shorter than the
number of bytes received plus 1, therefore, some data got lost.
One: BOV active
Zero: BOV inactive
FCSE: Framing Check
Sequence Error
FCSE indicates a mismatch between the FCS received and the FCS calculated
ACKE: Acknowledge
Error
ACKE indicates a physical violation or collision on ACK field of the frame when the TSS463 is
produced.
One: FCSE active
Zero: FCSE inactive
One: ACKE active
Zero: ACKE inactive
30
TSS461E
4194C–AUTO–01/06
TSS461E
Figure 18. ACKE Status Bit
DLC: Producer
EOD field
ACK field
expected
ACKE = 0
RAK = 0
received
ACKE = 1
received
ACKE = 1
received
ACKE = 1
RAK* = 1
*RAK: bit of the frame COMMAND field
EOD field
CV: Code Violation
ACK field
expected
ACKE = 0
received
ACKE = 1
received
ACKE = 1
received
ACKE = 1
CV indicates:
•
either a Manchester code violation (2 identical TS on Manchester bit), or a physical violation
(transmitted bit “dominant”, received bit “recessive”), on fields ID, COM, DATA and CRC, or
•
a physical violation or collision on field “preamble” and the “recessive” bit of the “Star Sync”
field.
One: CV active
Zero: CV inactive
31
4194C–AUTO–01/06
FV: Frame Violation
FV indicates a physical violation or collision on ACK field of the frame when the TSS463 is
consumed.
One: FV active
Zero: FV inactive
Figure 19. FV Status Bit
DLC: Consumer
EOD field
ACK field
expected
FV = 0
received
FV = 1
received
FV = 1
received
FV = 1
EOD field
ACK field
expected
FV = 0
received
FV = 1
received
FV = 1
received
FV = 1
Interrupt Status Register (0x09)
7
6
5
4
3
2
1
0
RST
0
0
TE
TOK
RE
ROK
RNOK
•
Read only register.
•
Default value after reset: 0×80
RST: Reset interrupt
RE indicates that the circuit has detected a valid reset command via the RESET pin or the reset
command bit GRES. This interrupt cannot be disabled, since its enable bit is set when a reset is
detected.
TE: Transmit Error
Status Flag (or
Exceeded Retry)
This flag is set only when the Max number of transmission (1+MR [3:0]) is reached with error of
transmission.
Figure 20. Exceeded retry with MR[3.0] = 3
1st TX
32
2nd TX
3rd TX
set TE
set CHER
set CHTx
TSS461E
4194C–AUTO–01/06
TSS461E
TOK: Transmit OK
Status Flag
RE: Receive Error
Status Flag
ROK: Receive “with
RAK (RAK=1)” OK
Status Flag
RNOK: Receive “with no
RAK (RAK=0)” OK
Status Flag
One: Status flag activated
Zero: No status flag.
Interrupt Enable Register (0x0A)
7
6
5
4
3
2
1
0
1
0
0
TEE
TOKE
REE
ROKE
RNOKE
•
Read/write register
•
Default value reset: 0x80
Note:
On reset the Reset Interrupt Enable bit is set to 1 instead of 0, as the general rule.
TEE: Transmit Error
Enable
TOKE: Transmission OK
Enable
REE: Reception Error
Enable
ROKE: Reception “with
RAK” OK Enable
RNOKE: Reception
“with no RAK” OK
Enable
One: IT enabled.
Zero: IT disabled.
Interrupt Reset Register (0x0B)
7
6
5
4
3
2
1
0
RSTR
0
0
TER
TOKR
RER
ROKR
RNOKR
•
Write only register.
•
Reserved bit: 5 and 6. This bit cannot be set by user; a zero must always be written to this
bit.
33
4194C–AUTO–01/06
RSTR: Reset Interrupt
Reset
TER: Transmit Error
Status Flag Reset
TOKR: Transmit OK
Status Flag Reset
RER: Receive Error
Status Flag Reset
ROKR: Receive “with
RAK” OK Status Flag
Reset
RNOKR: Receive “with
no RAK” OK Status Flag
Reset
One: Status flag reset
Zero: Status flag unchanged
6 TS
Set RXG
1 to 2 TS
Reset RXG, TXG
4 TS
Set TXG
BUS
ID+COM+DATA+CRC
ACK
SOF
EOD
Figure 21. Update of the Status Register
INT
Line Status Register (0x04)
4 TS
Write “IT Status Register”
Write “Last Error Register”
Write “Last Message Register”
Write “Message Status”
Write “Message Length & Status Register”
Channel Registers There is a total of 14 channel register sets, each occupying 8 bytes for addressing simplicity,
integrated into the circuit. Each set contains two 2 x 8-bit registers for the indentifier tag, indentifier mask and command fields plus two 1 x 8-bit registers for DMA pointers and message status.
The base_address of each set is: (0x10 + [0x08 * channel_number]).
When the TSS461E is reset either via the external reset pin or the general reset command, the
channel registers are not affected. For example, on power-up of the circuit, all the channel registers start with random values.
Due to this fact, the user should take care to initialize all the channel registers before exiting
from idle mode. The easiest way to disable a channel register is to set the received and transmitted bits to 1 in the Message Length & Status Register.
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TSS461E
4194C–AUTO–01/06
TSS461E
Table 9. Channel Register Sets Map
Channel Number
From
To
Channel Number
From
To
6
0x40
0x47
13
0x78
0x7F
5
0x38
0x3F
12
0x70
0x77
4
0x30
0x37
11
0x68
0x6F
3
0x28
0x2F
10
0x60
0x67
2
0x20
0x27
9
0x58
0x5F
1
0x18
0x1F
8
0x50
0x57
0
0x10
0x17
7
0x48
0x4F
Table 10. Channel Register Set Structure
Identifier Tag and
Command Registers
Reg. Name
Offset
Bit 7
Bit 6
Bit 5
Bit 4
ID_MASK
0x07
ID_MASK
0x06
(no register)
0x05
x
x
x
x
(no register)
0x04
x
x
x
x
MESS_L/
STA
0x03
MESS_PTR
0x02
ID_TAG/
CMD
0x01
ID_TAG
0x00
Bit 3
Bit 2
Bit 1
Bit 0
x
x
x
x
x
x
x
x
x
x
x
x
CHER
CHTx
CHRx
RAK
RNW
RTR
ID_M [3:0]
ID_M [11:4]
M_L [4:0]
DRACK
M_P [6:0]
ID_T [3: 0]
EXT
ID_T [11:4]
The identifier tag and command registers is located at the base_address and base_address + 1.
It allows the user to specify the full 12-bit identifier field of the ISO standard and the 4-bit
command.
•
7
6
5
4
3
2
1
0
ID_T 3
ID_T 2
ID_T 1
ID_T 0
EXT
RAK
RNW
RTR
7
6
5
4
3
2
1
0
ID_T 11
ID_T 10
ID_T 9
ID_T 8
ID_T 7
ID_T 6
ID_T 5
ID_T 4
base_address
+ 0x01
base_address
+ 0x00
Read/Write registers.
35
4194C–AUTO–01/06
ID_T [11:0]: Identifier
Tag
Upon a reception hit (i.e, a good comparison between the identifier received and an identifier
specified, taking the comparison mask into account, as well as a status and command indicating
a message to be received, the identifier tag bits value will be rewritten with the identifier bits
actually received.
EXT, RAK, RNW &
RTR: (See
section “Retries,
Rearbitrate and Abort”)
No comparison will be done on the command bits, except on EXT bit. The RAK, RNW and RTR
bits will be written into the first byte of the Message upon a reception hit.
The RNW and RTR bits, as well as the status bits in the length and status register, must be in a
valid position for reception or transmission. If not, the message corresponding to this identifier is
considered as inactive or invalid.
The way of knowing if an acknowledge sequence was requested or not is to check the first byte
of the Message.
Message Pointer
Register
The message pointer register at address (base_address + 0x02) is 8 bits wide. It indicates
where, in the Message DATA RAM area, the message buffer is located.
•
DRAK: Disable RAK
(Used in 'Spy Mode')
7
6
5
4
3
2
1
0
DRAK
M_P 6
M_P 5
M_P 4
M_P 3
M_P 2
M_P 1
M_P 0
base_address
+ 0x02
Read/Write register
In reception: whatever is the RAK bit of the incoming valid frame, no ACK answer will be set. If
the message was successfully received, an IT is set (ROK or RNOK).
In transmission: no action.
One: disable active, 'spy' mode.
Zero: disable inactive, normal operation.
M_P [6:0]: Message
Pointer
Since the Message DATA RAM area base address is 0x80, the value in this register is the offset
from that address. If the message buffer length value is illegal (i.e. zero), this register is redefined as being a link pointer, thus containing the channel number of the channel that contains the
actual message pointer, message length and received status. However, the identifier, mask,
error and transmitted status used will be the originally matched channel. In any case, if a link is
intended, the three high bits of M_P [6:0] should be set to 0.
This allows several channels to use the same actual reception buffer in Message DATA RAM,
thus diminishing the memory usage.
Note that only 1 level of link is supported.
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4194C–AUTO–01/06
TSS461E
Message Length And
Status Register
The message length and status register at address (base_address + 0x03) is also 8 bits wide. It
indicates the length reserved for the message in the Message DATA RAM area.
•
M_L [4:0]: Message
Length
7
6
5
4
3
2
1
0
M_L 4
M_L 3
M_L 2
M_L 1
M_L 0
CHER
CHTx
CHRx
base_address
+ 0x03
Read/Write register.
The 5 high bits of this register allow the user to specify either the length of the message to be
transmitted, or the maximum length of a message receivable in the pointed reception buffer.
Note, that the first byte in this register does not contain data, but the length of the message
received. This implies that the length value has to be equal to or greater than the maximum
length of a message to be received in this buffer (or the length of a message to be transmitted)
plus 1. Thus allowing a maximum length of 30 bytes and a minimum length of 0 byte.
If the value of this field is "illegal" (i.e 0x00) then this message pointer is defined as being a link
(see section “Message Pointer Register” and section “Linked Channels”).
M_L [4:0] = 0x00
Linked channel
M_L [4:0] = 0x01
Frame with no DATA field (*)
M_L [4:0] = 0x02
Frame with 1 DATA byte
-------
----------------------
M_L [4:0] = 0x1D
Frame with 28 DATA bytes
M_L [4:0] = 0x1E
Frame with 29 DATA bytes
M_L [4:0] = 0x1F
Frame with 30 DATA bytes
(*) Different of a reply request frame with no in-frame reply (deferred reply).
CHER: Channel Error
Status and Abort
Command
As status, this bit is set by the TSS461E when error occurs in transmission or on a received
frame. The user must reset it.
To abort the transmission defined in the channel, this bit can be set to1 by the user (see
section “Retries, Rearbitrate and Abort” and section “Abort”).
CHTx: Channel
Transmitted and
Transmit Enable
Command
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4194C–AUTO–01/06
CHRx: Channel
Received and Receive
Enable Command
The two low order bits of this register contain the message status. Together with the RNW and
RTR bits of the command register (base_address + 0x01), they define the message type of this
channel (seesection “Messages Types”). As a general rule (see section “Abort”), the status bits
are only set by the TSS461E, so the user must reset them to perform a transmission
(CHTx)
or/and a reception (CHRx). The received and transmitted bits are only set if the corresponding
frame is without errors or if the retry count has been exceeded.
Identifier Mask
Registers
The Identifier Mask registers (base_address + 0x06 and base_address + 0x07) allow bitwise
masking of the comparison between the identifier received and the identifier specified.
•
ID_M [11:0]: Identifier
Mask
38
7
6
5
4
3
2
1
0
ID_M 3
ID_M 2
ID_M 1
ID_M 0
x
x
x
x
7
6
5
4
3
2
1
0
ID_M 11
ID_M 10
ID_M 9
ID_M 8
ID_M 7
ID_M 6
ID_M 5
ID_M 4
Read/Write registers
A value of 1 indicates comparison enabled.
A value of 0 indicates comparison disabled.
TSS461E
4194C–AUTO–01/06
TSS461E
Mailbox
The mailbox contains all the messages received or to be transmitted. Each messages is link to a
channel. The Mailbox RAM area has 128 bytes and is mapped from 0x80 to 0xFF (see
section “Mapping”).
The message (or message buffer) is composed of:
•
1 byte of message status (only used in receiving)
•
Bytes of data. These data are the bytes of the DATA field of the frame with the same
organization.
The message is pointed by the Message Pointer Register of the channel, the length of the message is given by the Message Length & Status Register of the channel (section “Message
Pointer Register” and section “Message Length And Status Register”). This area is a pure RAM,
it contains a random value after reset.
Figure 22. Message Buffer Structure for Reception
Message Length & Status Register
Message Pointer Register
CHER CHTx CHRx
( M_L >= n + 2 )
M_L [4..0]
M_P [6..0]
DRAK
Message
received DATA n
M_P + 0x80 + n + 2
received DATA 0
Note:
DATA n
FCS
ACK
DATA 0
M_P + 0x80
EOD
ID [11..0]
RTR
SOF
EXT
RAK
RNW
RAK RNW RTR
M_L [4..0] = n+1
receivedreceivedreceived
received
EOF
Received DATA Frame, immediate or deffered reply
39
4194C–AUTO–01/06
Figure 23. Message Buffer Structure for Transmission
Message Length & Status Register
M_L [4..0]
Message Pointer Register
CHER CHTx CHRx
M_P [6..0]
DRAK
DATA n
Transmitted
DATA 0
M_P + 0x80 + n + 2
RTR
ID [11..0]
RNW
SOF
EXT
RAK
(Nothing)
M_P + 0x80
DATA 0
DATA n
FCS
ACK
Transmitted
EOD
( M_L >= n + 2 )
Message
EOF
Transmitted DATA Frame
Message Status (Pointed by: Message Pointer Register)
7
6
5
4
3
2
1
0
RRAK
RRNW
RRTR
RM_L4
RM_L3
RM_L2
RM_L1
RM_L0
(no significant value in case of message to be transmitted)
RRAK: Received RAK
Bit
This bit is the RAK bit coming from the COM field of the received frame.
RRNW: Received RNW
Bit
This bit is the RNW bit coming from the COM field of the received frame.
RRTR: Received RTR
Bit
This bit is the RTR bit coming from the COM field of the received frame.
RM_L[4:0]: Message
Length of the Received
Frame
If the DATA field of the received frame included DATA0 to DATAn, RM_L[4:0] = n+1, even if the
reserved length (Message Length & Status Register) is larger.
40
TSS461E
4194C–AUTO–01/06
TSS461E
Figure 24. Message Status Updating
Frame Type
Node x
Communication
I, P
Node A
C
Data Frame
Immediate
Reply
Deferred
Reply
Message Status on Node A after IT(*)
I, C
RAK
RNW
RTR
RAK
RNW
RTR
RAK
RNW
RTR
P
I, C
C
Deferred
Reply
P: Producer
previous
value
P
previous
value
I, P
Data Frame
Immediate
Reply
length
previous values
P
I, C
P
RAK
RNW
RTR
length
RAK
RNW
RTR
length
I, C
I: Initiator
C: Consumer
(*) After IT ROK or RNOK. In case of IT RE, the values can be erroneous.
Message Data (String Pointed by: Message Pointer Register + 1)
7
6
5
4
3
2
1
0
---
---
-- - -
---
DATAn
---
---
---
--DATA0
DATA0 is the first received (or transmitted) byte, DATAn is the last one.
Notes:
1. If the length reserved (in the message length & status register) for an incoming frame is 2
bytes greater or more, the TSS461E will write the 2 bytes of the CRC field in the message
string just after DATAn.
Because the VAN frame does not contain a message length, the only way for the component
to know the length of the DATA field is either the message length register value, or the EOD
field detection. When the reserved length is too large, at the moment when it detects the EOD,
the TSS461E has already written the 2 bytes of the CRC field, considering these bytes as normal DATA.
2. The Mailbox RAM area is a circular buffer. The next location after 0xFF is 0x80.
41
4194C–AUTO–01/06
Messages
Types
There are 5 basic message types defined in the TSS461E. Two of them (transmit and receive
message types) correspond to the normal frame, and the rest correspond to the different versions of reply frames.
Transmit Message
RNW
RTR
CHTx
CHRx
Initial Setup
0
0
0
Don’t Care
After Transmission
0
0
1
Unchanged
To transmit a normal data frame on the VAN bus, the user must program an identifier as a
Transmit Message. The TSS461E will then transmit this message on the bus until it has succeeded or the retry count is exceeded.
Receive Message
RNW
RTR
CHTx
CHRx
Initial Setup
0
1
Don’t Care
0
After Transmission
0
1
Unchanged
1
The opposite of the transmit message type is the Receive Message type. This message type will
not generate any frames on the bus. Instead, it will listen to the bus until a frame passes that
matches its identifier, with the mask taken into account, and then receive the data in that frame.
The data received will be stored in the message buffer and the length of the message received
is stored in the first byte of the message buffer.
The actual identifier received is stored in the identifier register itself. This identifier may differ
from the identifier specified in the register due to the effect of the mask register.
Normally, this should not interfere with the next identifier comparison since the bits that may differ are masked via the mask register.
Reply Request Message
RNW
RTR
CHTx
CHRx
Initial Setup
1
1
0
0
After Transmission
(Waiting for reply)
1
1
1
0
After Reception
(of reply)
1
1
1
1
The Reply Request Message type is a demand to transmit on the VAN bus a reply request.
When this message type is programmed, three things can happen.
First, no other modules on the bus responded with an in-frame reply, in this case the TSS461E
will set the message type to the after transmission state. When this message type is programmed, the TSS461E will listen on the bus for a deferred reply frame matching this identifier,
without transmitting the reply request.
42
TSS461E
4194C–AUTO–01/06
TSS461E
Second, another module on the bus replies with an in-frame reply. In this case the message type
will pass immediately into the after reception state, without passing the after transmission state.
Reply Request Message Without Transmission
RNW
RTR
CHTx
CHRx
Initial Setup
1
1
Don’t Care
0
After Reception
1
1
Unchanged
1
Third, the TSS461E has not yet started to transmit the reply request, when another module
either requests a reply, and gets it, or transmits a deferred reply. Warning! This should be
avoided as it may result in an illegal message type (Illegal reply Request).
Immediate Reply Message
RNW
RTR
CHTx
CHRx
Initial Setup
1
0
0
0
After Transmission
1
0
1
1
The immediate Reply Message will attempt to transmit an in-frame reply, using the data in the
message buffer. A deferred Reply Message is shown below.
Deferred Reply Message
RNW
RTR
CHTx
CHRx
Initial Setup
1
0
0
1
After Reception
(of Reply Request)
1
0
1
1
This message type will immediately transmit a deferred reply frame.
Reply Request Detection Message
RNW
RTR
CHTx
CHRx
Initial Setup
1
0
1
0
After Reception
1
0
1
1
Finally, there is the Reply Request Detector Message type. Its purpose is to receive a reply
request frame and notify the processor, without transmitting an in-frame reply.
Inactive Message
RNW
RTR
CHTx
CHRx
Recommended
Don’t Care
Don’t Care
1
1
After Transmission
0
0
1
Don’t care
After Reception
0
1
Don’t Care
1
Illegal Reply Request
1
1
0
1
The table above shows all inactive messages types. The last combination will transmit a reply
request, but will not receive the reply since its buffer is tagged as occupied.
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4194C–AUTO–01/06
Priority Among
the Different
Channels
The priority handling on the VAN bus is already explained in the Line Interface section. The priorities for the messages in the TSS461E is, however, slightly different.
For instance, it's possible that an identifier matches two or more of the identifiers programmed
into the registers. In this case, it is the lowest identifier number that has priority. i.e., if both identifier 5 and 10 match the identifier received, it is the identifier 5 that will receive the message.
However, since the identifier 5 will become an inactive message when it has received the frame,
the next time the same identifier is seen on the bus, the corresponding data will be received by
identifier 10.
The same is valid for messages to be transmitted, i.e., if two or more messages are ready to be
transmitted, it is the one with the lowest identifier number that will get priority.
44
TSS461E
4194C–AUTO–01/06
TSS461E
Retries,
Rearbitrate and
Abort
Retries and rearbitrate commands are located, in the Transmit Control Register and in the Command Register, respectively. An abort command is located in each channel register set, in the
Message Length & Status Register (base_address + 0x03). These three commands are available only when the TSS461E is producer.
Figure 25. Transmit Function
Activate
Ch. Enabled in
Xmit Mode?
no
yes
Select the lowest
Ch. number and
load”Max - retries”
Disable of
current Ch.
Abort activated
on current Ch.?
yes
no
Wait for bus free
(EOF+IFS= 12 Timeslots)
Transmit frame
and wait for the end
Decrement
retry counter
abort
Abort required
on current Ch.
rearbitrate?
rearbitrate
no
yes
Retries
Retry needed?
no
The purpose of retries feature is to provide, the capability of retrying a transmit request in case
of failure, when a node tries to reach another node, either on normal DATA frame or on REPLY
REQUEST frame.
The maximum of retries is programmable through MR[3:0] of the Transmit Control Register
(0x01). When a channel is enable – bit CHTx= 0 of Message Length & Status Register, a 4-bit
counter is loaded with MR[3:0]. At each attempt, this counter will be countdown. To 0, an IT TE
is set in the Interrupt Status Register (0x09), and the transmission is stopped.
MR[3:0] = 1 indicates 1 retry, hence 2 transmission attempts will be performed (see Table 4).
The number of retries performed, as well as the current channel number associated, can be
read in the Transmission Status Register (0x05).
The Last Error Status Register (0x07) informs about the trouble encountered:
45
4194C–AUTO–01/06
•
•
Failure cases:- Code viol (CV error bit)
–
Acknowledge error (ACKE error bit)
–
CRC error (FCSE error bit)
It should be noticed that contention is considered as normal CSMA/CD protocol and,
therefore, is not taken into account in failure cases. So, an 'infinite' number of attempts can
be performed if bus contention occurs continuously.
There is only one retries counter for all channels. When the user writes the Max_Retries value,
all channels start their transmission with this parameter.
Rearbitrate
The purpose of rearbitrate feature is to postpone a channel already in transmission in order to
authorize an higher priority (see section “Priority Among the Different Channels”) message to be
transmit.
Typical Example
•
Max_retries = 1 (2 transmissions attempts).
•
If Ch 8 is in a the retry loop and the user wants to transmit the Ch 5 without waiting the end
of the loop, the user can use the rearbitrate command.
•
Then, the TSS461E will wait the end of the current transmission, reload the retries counter
and enable the Ch 5 to transmit.
•
At the end of this transmission Ch5, either when the attempt is successful or either when the
exceeded retry count is reached, the retries counter is reloaded and the transmission is
activated for the Ch 8 again.
46
Second attempt
Xmit Ch8
(Retries - 1)
First attempt
Xmit Ch8
* (not seen by application means nogeneration)
IT
Set CHER & CHTx /Ch8,
and set ITTE
Ex: set FSCE status bit
Ex: FCS Error
(Load Max-retries)
(not seen by application)
Delay
Viol
EOF+IFS
Xmit Ch5
First attempt
Xmit Ch8
Delay
Viol
Set CHTx/Ch5 & ITROK
(Load Max-retries)
Ex: FCS Error
* (not seen by application)
(Activate Ch5)
Rearbitrate
(Load Max-retries)
Figure 26. Rearbitrate Example
stand-by
Delay
Viol
EOF+IFS: 8 + 4 Timeslots
Delay Viol: 12 Timeslots
TSS461E
4194C–AUTO–01/06
TSS461E
Set CHER & CHTx /Ch8,
and set ITTE
Ex: set FSCE status bit
Ex: FCS Error
(not seen by application)
(Retries - 1)
First attempt
Xmit Ch8
* (not seen by application means no IT generation)
Second attempt
Xmit Ch8
Delay
Viol
EOF+IFS
Xmit Ch5
First attempt
Xmit Ch8
Delay
Viol
(Load Max-retries)
Set CHTx/Ch5 & ITROK
Idle command
(Load Max-retries)
Ex: FCS Error
* (not seen by application)
Rearbitrate
(Activate Ch5)
(Load Max-retries)
Figure 27. Idle and Rearbitrate Example
Idle
Delay
Viol
EOF+IFS: 8 + 4 Timeslots
Delay Viol: 12 Timeslots
If the user sets the idle bit anywhere (after rearbitrate), the idle mode is entered only at the end
of all the transmit attempts (for more information about idle command, see section “Activate, Idle
and Sleep Modes”.
Disable Channel After
Rearbitrate
Note:
Abort
First attempt
Xmit Ch8
EOF+IFS
Xmit Ch5
First attempt
Xmit Ch8
Viol
Set CHER & CHTx /C
and set ITTE
Ex: set FSCE status
Ex: FCS Error
(not seen by application)
Delay
Delay
Viol
Viol
econd attempt
Xmit Ch8
Delay
(Retries - 1)
(Load Max-retries)
Set CHTx/Ch5 & ITRO
(Load Max-retries)
Ex: FCS Error
* (not seen by application)
(Activate Ch5)
Rearbitrate
(Load Max-retries)
Figure 28. Disable Channel After Rearbitrate Example
stand-by
EOF+IFS: 8 + 4 Timeslots
Delay Viol: 12 Timeslots
In this case, the TSS461E completes the current attempt (Ch8) and lets the transmission go to the
new channel (Ch5 if validated); otherwise, it stops all attempts on the current channel.
An abort command is dedicated to channels already enabled in transmission or in-frame
response. For example, this command can be used to break the retry procedure on one
channel.
47
4194C–AUTO–01/06
Abort channel is done by setting the Error bit (CHER) in the Message Length & Status Register
(base_address + 0x02). This command is taken into account if the channel aborted is not transmitted. When this abort command is really done, the TSS461E set to 1 the Transmitted bit
(CHTx) of the Message Length & Status Register.
The abort mechanism is integrated into the transmit function. This means, abort, priority and
retries live together in the transmit function.
Set CHTx/Ch13
IT ROK
SetorCHTx
CHER/Ch6 &or IT RE
Set CHTx/Ch6 & ITROK
if success
Set CHTx/Ch6 & ITROK
if success
Set CHTx/Ch4 &ITROK
Abort Ch4 (during Xmit)
Abort Ch13 (before Xmit)
Activate
Abort Ch0 (before Xmit)
Set CHTx/Ch0
Ch’s initialization
Reset
Figure 29. Abort Example
48
Xmit Ch6
if previously fail
Xmit Ch6
if previously fail
Xmit Ch6
Xmit Ch4
12 Timeslots
TSS461E
4194C–AUTO–01/06
TSS461E
Activate, Idle
and Sleep
Modes
Sleep, idle and activate commands are located in the Command Register (0x03). These three
commands are general commands for the TSS461E.
Idle and Activate
Commands
After reset, the TSS461E starts in idle mode. In this mode, the oscillator operates (CKOUT pin
active) but the circuit cannot transmit or receive anything on the VAN bus. The TxD output (pin
18) is in three-state mode, a pull-up resistor must be provided externally or by the line driver to
avoid floating state on the VAN bus.
To activate the TSS461E, the user must set the activate bit (ACTI) and reset the idle bit (IDLE).
Figure 30. Idle and Activate Timings
Idle mode
Activate mode
SOF
RxD
Activate command
after reset
SOF
TxD
8 TS
12 TS
3 TS
(max)
TS: Timeslot period
Idle mode
ACK
FCS
EOD
Activate mode
RxD
Idle command
INT
4 TS
5 TS
In both cases, the idle state can be verified by reading the Line Status register (0x04).
Sleep Command
If the user sets the sleep bit (SLEEP), the TSS461E enters in sleep mode, whatever are the values of activate and idle bits. All non-user registers are set-up to reduce the power consumption
and the internal oscillator is immediately stopped. However, all user registers (accessible by µP
bus) are always available by the user
To exit from this mode, the user must set either the idle bit or the activate bit.
In a typical application (Figure 12) using the CKOUT feature (pin 12), if the TSS461E is put in
sleep mode, the clock provided to the microcontroller is stopped. So, the system does not run
and the only way to awake this application is an external reset.
49
4194C–AUTO–01/06
Linked
Channels
The linkage feature allows two channels to share the same Message area, the message pointer
and the message length assumes the following property:
•
Zero value as message length (M_L [4:0] - base_address + 0x03) declares the channel
linked to another channel.
•
The number of this other channel is defined in the message pointer field (M_P [6:0] base_address + 0x02).
•
The pointer and the length values for the Message area are defined only once time, in the
register set of this other Channel.
Only one level of linkage can be created. For example, (see Figure 30) a Channel k can be
linked to the Channel i but not to Channel j, already defined as linked to Channel i.
All the others can be different between the two channels, for example the ID_Tag.
Figure 31. Linkage Mechanism
The Channel j linked
Channel i and j
....
share the same
Message area
to the Channel i
ID_Mask j (msb)
0x00
DRAK
ID_Tag j (lsb)
--- Message forChannels i & j ---
DATA n
CHER CHTx CHRx
i
EXT RAK RNW RTR
ID_Tag j (msb)
--- Channel i ---
Length = n+2
--- Channel j ---
ID_Mask j (lsb)
ID_Mask i (lsb)
ID_Mask i (msb)
Mess_Len = n+2CHER CHTx CHRx
Mess_Ptr
DRAK
ID_Tag i (lsb)
EXT RAK RNW RTR
DATA 0
Message Status
ID_Tag i (msb)
This Message Area sharing permits either optimizing the allocation of the 128 bytes of DATA,
performing some special communications between the different nodes of the network.
50
TSS461E
4194C–AUTO–01/06
TSS461E
Electrical Characteristics
Absolute Maximum Ratings
Ambient temperature under Bias:
Note:
A = Automotive .................................................-40°C to 125°C
Storage Temperature ........................................-65°C to 150°C
Voltage on VCC to VSS ......................................... -0.5 to +7.0 V
Voltage on any Pin to VSS ...................... -0.5 V to VCC + 0.5 V
DC
Characteristics
Symbol
TA = -40°C to 125°C; VCC = 5 V + 10%; VSS = 0 V
Parameter
Min
Max
Type
VIL
Input Low Voltage (except RESET and
XTAL1)
-0.5
0.8
V
VIH
Input High Voltage (except RESET and
XTAL1)
2.0
VCC+0.5
V
VIL1
Input Low Voltage (RESET and XTAL1)
-0.5
0.3·VCC
V
VIH1
Input High Voltage (RESET and XTAL1)
0.7 VCC
VCC+0.5
V
VOL
Output Low Voltage
0.4
V
VOH
Output High Voltage
IL
See Figure 2
IOL = 3.2 mA, Vcc min
IOH = -3.2 mA, Vcc min
0 < VIN < VCC
kΩ
0 < VIN < VCC
10
pF
Not tested
50
μA
(Note 1)
Power Supply Current
4
mA
(Notes 2, 4)
Idle or Active Mode
15
mA
(Notes 3, 4)
Input Pull-down Resistor
CIO
I/O Buffer Capacitance
ICCOP
Test Conditions
μA
RPD
1.
2.
3.
4.
5.
2.4
Input Leakage Current
ICCSB
Notes:
Stresses at or above those listed under "Absolute
Maximum Ratings" may cause permanent damage to
the device. This is a stress rating only and functional
operation of the device at these or any other conditions exceeding those indicated in the operational
sections of this specification is not implied. Exposure
to absolute maximum rating conditions may affect
device reliability.
Power Supply Current
Sleep Mode
+5
110
Sleep Mode ICCSB is measured according to Figure 40 with a VSS Clock Signal.
Active mode ICCOP is measured at: XTAL = 1 MHz clock, VAN speed rate = 62.5 KTS/s.
Active mode ICCOP is measured at: XTAL = 16 MHz clock, VAN speed rate = 250 KTS/s.
ICC is a function of the Clock Frequency. Figure 8 displays a graph showing ICC versus Clock frequency.
RESET, RxD0, RxD1, RxD2 inputs.
51
4194C–AUTO–01/06
Figure 32. ICC
Icc
TXD
CLOCK SIGNAL
N.C.
Figure 33. ICC Versus Clock Frequency at 250 KTimeslot/s
mA
9
8.5
8
7.5
MHz
2
52
4
6
8
TSS461E
4194C–AUTO–01/06
TSS461E
AC Characteristics
Microprocessor
Interface
TA = -40°C to 125°C; VCC = 5V + 10%; VSS = 0V
Symbol
TRESET
Characteristic
Min
Max
Unit
RESET High Pulse Width (For Power-up Reset)
15
ns
1
TLHLL
ALE High Pulse Width
10
ns
2
TAVLL
Address Valid to ALE Low Setup Time
10
ns
3
TLLAX
ALE Low to Address Invalid Hold Time
10
ns
4
TAVWL
Address Valid to Command Active Time
20
ns
5
TDVWH
Data Valid to Write Inactive Setup Time
10
ns
6
TWHDX
Write Inactive to Data Invalid Hold Time
12
ns
7
TWHLH
Write Inactive to ALE High Recovery Time
20
ns
8
TRLDV
Read Active to Data Valid Access Time
110
ns
9
TRHDZ
Read Inactive to Data Float Time
20
ns
10
TWHRLIZ
Write Inactive or Read Active to IRQ Float Time
90
ns
11
TIZIL
20
ns
IRQ Float Pulse Width
2
53
4194C–AUTO–01/06
Oscillator
Characteristics
Figure 34. C2 Versus Frequency
pF
200
100
33
1
Note:
External Clock
Drive
Characteristics
(XTAL1)
2
4
8
MHz
C1 (no capacitance needed) see Figure 2.
Symbol
Parameter
Min
TCHCH
Oscillator Period
120
ns
TCHCX
High Time
20
ns
TCLCX
Low Time
20
ns
TCLCH
Rise Time
20
ns
TCHCL
Fall Time
20
ns
t CHCL
XTAL1
V IH
Max
Unit
t CLCH
V IH
V IH
V IL
V IL
t CHCX
t CLCX
t CHCH
54
TSS461E
4194C–AUTO–01/06
TSS461E
Packaging Information
24
SO
MM
INCH
A
2.35
2.65
0.093
0.104
A1
0.10
0.30
0.004
0.012
B
0.35
0.49
0.014
0.019
C
0.23
0.32
0.009
0.013
D
15.20
15.60
0.599
0.614
E
7.40
7.60
0.291
0.299
e
1.27
BSC
0.050
BSC
H
10.00
10.65
0.394
0.419
h
0.25
0.75
0.010
0.029
L
0.40
1.27
0.016
0.050
N
24
24
a
0°
0°
55
4194C–AUTO–01/06
Ordering Information
Part Number
Supply Voltage
Temperature Range
Package
Packing
TSS461E-TDSA-9
5V +10%
-40°C to +125°C
SO24
Tube
TSS461E-TDRA-9
5V +10%
-40°C to +125°C
SO24
Tape & Reel
TSS461E-TDRZ-9(1)
5V +10%
-40°C to +125°C
SO24
Tape & Reel
Note:
56
1. These products are available in ROHS version.
TSS461E
4194C–AUTO–01/06
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4194C–AUTO–01/06