The TSB41AB1 provides the digital and analog transceiver functions needed to implement a one-port node in
a cable-based IEEE 1394 network. The cable port incorporates one differential line transceiver. The transceiver
includes circuitry to monitor the line conditions as needed for determining connection status, for initialization
and arbitration, and for packet reception and transmission. The TSB41AB1 is designed to interface with a link
layer controller (LLC), such as the TSB12LV21, TSB12LV22, TSB12LV23, TSB12LV26, TSB12LV31,
TSB12LV41, TSB12LV42, or TSB12LV01A.
The TSB41AB1 requires only an external 24.576-MHz crystal as a reference. An external clock may be provided
instead of a crystal. An internal oscillator drives an internal phase-locked loop (PLL), which generates the
required 393.216-MHz reference signal. This reference signal is internally divided to provide the clock signals
used to control transmission of the outbound encoded strobe and data information. A 49.152-MHz clock signal
is supplied to the associated LLC for synchronization of the two chips and is used for resynchronization of the
received data. The power-down (PD) function, when enabled by asserting the PD terminal high, stops operation
of the PLL.
The TSB41AB1 supports an optional isolation barrier between itself and its LLC. When the ISO\ input terminal
is tied high, the LLC interface outputs behave normally. When the ISO\ terminal is tied low, internal differentiating
logic is enabled, and the outputs are driven such that they can be coupled through a capacitive or transformer
galvanic isolation barrier as described in Annex J of IEEE Std 1394-1995 and in IEEE 1394a-2000 (section
5.9.4) (hereinafter referred to as Annex J type isolation). To operate with TI bus holder isolation the ISO\ terminal
on the PHY must be high.
Data bits to be transmitted through the cable port are received from the LLC on two, four or eight parallel paths
(depending on the requested transmission speed) and are latched internally in the TSB41AB1 in
synchronization with the 49.152-MHz system clock. These bits are combined serially, encoded, and transmitted
at 98.304, 196.608, or 393.216 Mbits/s (referred to as S100, S200, and S400 speeds, respectively) as the
outbound data-strobe information stream. During transmission, the encoded data information is transmitted
differentially on the TPB cable pair, and the encoded strobe information is transmitted differentially on the TPA
cable pair.
During packet reception the TPA and TPB transmitters of the receiving cable port are disabled, and the receivers
for that port are enabled. The encoded data information is received on the TPA cable pair, and the encoded
strobe information is received on the TPB cable pair. The received data-strobe information is decoded to recover
the receive clock signal and the serial data bits. The serial data bits are split into two-, four-, or eight-bit parallel
streams (depending upon the indicated receive speed), resynchronized to the local 49.152-MHz system clock
and sent to the associated LLC.
Both the TPA and TPB cable interfaces incorporate differential comparators to monitor the line states during
initialization and arbitration. The outputs of these comparators are used by the internal logic to determine the
arbitration status. The TPA channel monitors the incoming cable common-mode voltage. The value of this
common-mode voltage is used during arbitration to set the speed of the next packet transmission. In addition,
the TPB channel monitors the incoming cable common-mode voltage on the TPB pair for the presence of the
remotely supplied twisted-pair bias voltage.
The TSB41AB1 provides a 1.86-V nominal bias voltage at the TPBIAS terminal for port termination. This bias
voltage, when seen through a cable by a remote receiver, indicates the presence of an active connection. This
bias voltage source must be stabilized by an external filter capacitor of 1 µF. TPBIAS is typically VDD–0.2 V when
the port is not connected to another node.
The line drivers in the TSB41AB1 operate in a high-impedance current mode, and are designed to work with
external 112-
resistors. The midpoint of the pair of resistors that is directly connected to the twisted-pair-A terminals is
connected to its corresponding TPBIAS voltage terminal. The midpoint of the pair of resistors that is directly
connected to the twisted-pair-B terminals is coupled to ground through a parallel R-C network with
recommended values of 5 k
±1.0%.
When the power supply of the TSB41AB1 is off while the twisted-pair cables are connected, the TSB41AB1
transmitter and receiver circuitry presents a high impedance to the cable and does not load the TPBIAS voltage
at the other end of the cable. Fail-safe circuitry blocks any leakage path from the port back to the device power
plane.
The TESTM, SE, and SM terminals are used to set up various manufacturing test conditions. For normal
operation, the TESTM terminal should be connected to VDD through a 1-k
resistor, and SM should be connected directly to ground.
Four package terminals are used as inputs to set the default value for four configuration status bits in the self-ID
packet, and are tied high through a 1-k. See Table 9 for power-class encoding. The C/LKON
terminal is used as an input to indicate that the node is a contender for either isochronous resource manager
(IRM) or for bus manager (BM).</p>
<p>The TSB41AB1 supports suspend/resume as defined in the IEEE 1394a-2000 specification. The suspend
mechanism allows pairs of directly connected ports to be placed into a low-power state (suspended state) while
maintaining a port-to-port connection between bus segments. While in the suspended state, a port is unable
to transmit or receive data transaction packets. However, a port in the suspended state is capable of detecting
connection status changes and detecting incoming TPBIAS. When the port of the TSB41AB1 is suspended,
all circuits except the band gap reference generator and bias detection circuit is powered down, resulting in
significant power savings. For additional details of suspend/resume operation see IEEE 1394a-2000. The use
of suspend/resume is recommended for new designs.</p>
<p>The port transmitter and receiver circuitry is disabled during power down (when the PD input terminal is asserted
high), during reset (when the RESET\ input terminal is asserted low), when no active cable is connected to the
port, or when controlled by the internal arbitration logic. The TPBIAS output is disabled during power down,
during reset, or when the port is disabled as commanded by the LLC.</p>
<p>The cable-not-active (CNA) output terminal (64-terminal PAP package only) is asserted high when there are
no twisted-pair cable ports receiving incoming bias (that is, they are either disconnected or suspended), and
can be used along with LPS to determine when to power down the TSB41AB1. The CNA output is not
debounced. When the PD terminal is asserted high, the CNA detection circuitry is enabled (regardless of the
previous state of the ports) and a pulldown is activated on the RESET\ terminal so as to force a reset of the
TSB41AB1 internal logic.</p>
<p>The LPS (link power status) terminal works with the C/LKON terminal to manage the power usage in the node.
The LPS signal from the LLC is used in conjunction with the LCtrl bit (see Table 1 and Table 2 in the Application
Information section) to indicate the active/power status of the LLC. The LPS signal is also used to reset, disable,
and initialize the PHY-LLC interface (the state of the PHY-LLC interface is controlled solely by the LPS input,
regardless of the state of the LCtrl bit).</p>
<p>The LPS input is considered inactive if it remains low for more than 2.6 µs and is considered active otherwise.
When the TSB41AB1 detects that LPS is inactive, it places the PHY-LLC interface into a low-power reset state
in which the CTL and D outputs are held in the logic zero state and the LREQ input is ignored; however, the
SYSCLK output remains active. If the LPS input remains low for more than 26 µs, the PHY-LLC interface is put
into a low-power disabled state in which the SYSCLK output is also held inactive. The PHY-LLC interface is also
held in the disabled state during hardware reset. The TSB41AB1 continues the necessary repeater functions required for normal network operation regardless of the state of the PHY-LLC interface. When the interface is
in the reset or disabled state and LPS is again observed active, the PHY initializes the interface and returns it
to normal operation.</p>
<p>When the PHY-LLC interface is in the low-power disabled state, the TSB41AB1 automatically enters a
low-power mode if the port is inactive (disconnected, disabled, or suspended). In this low-power mode, the
TSB41AB1 disables its internal clock generators and also disables various voltage and current reference
circuits depending on the state of the port (some reference circuitry must remain active in order to detect new
cable connections, disconnections, or incoming TPBIAS, for example). The lowest power consumption (the
ultralow-power sleep mode) is attained when the port is either disconnected, or disabled with the port interrupt
enable bit cleared. The TSB41AB1 exits the low-power mode when the LPS input is asserted high or when a
port event occurs which requires that the TSB41AB1 become active in order to respond to the event or to notify
the LLC of the event (for example, incoming bias is detected on a suspended port, a disconnection is detected
on a suspended port, a new connection is detected on a nondisabled port, etc.). The SYSCLK output becomes
active (and the PHY-LLC interface is initialized and becomes operative) within 7.3 ms after LPS is asserted high
when the TSB41AB1 is in the low-power mode.</p>
<p>The PHY uses the C/LKON terminal to notify the LLC to power up and become active. When activated, the
C/LKON signal is a square wave of approximately 163-ns period. The PHY activates the C/LKON output when
the LLC is inactive and a wake-up event occurs. The LLC is considered inactive when either the LPS input is
inactive, as described above, or the LCtrl bit is cleared to 0. A wake-up event occurs when a link-on PHY packet
addressed to this node is received, or when a PHY interrupt occurs. The PHY deasserts the C/LKON output
when the LLC becomes active (both LPS active and the LCtrl bit set to 1). The PHY also deasserts the C/LKON
output when a bus reset occurs unless a PHY interrupt condition exists which would otherwise cause C/LKON
to be active.</p></p> </ti-view-more> <div class=)
The TSB41AB1 provides the digital and analog transceiver functions needed to implement a one-port node in
a cable-based IEEE 1394 network. The cable port incorporates one differential line transceiver. The transceiver
includes circuitry to monitor the line conditions as needed for determining connection status, for initialization
and arbitration, and for packet reception and transmission. The TSB41AB1 is designed to interface with a link
layer controller (LLC), such as the TSB12LV21, TSB12LV22, TSB12LV23, TSB12LV26, TSB12LV31,
TSB12LV41, TSB12LV42, or TSB12LV01A.
The TSB41AB1 requires only an external 24.576-MHz crystal as a reference. An external clock may be provided
instead of a crystal. An internal oscillator drives an internal phase-locked loop (PLL), which generates the
required 393.216-MHz reference signal. This reference signal is internally divided to provide the clock signals
used to control transmission of the outbound encoded strobe and data information. A 49.152-MHz clock signal
is supplied to the associated LLC for synchronization of the two chips and is used for resynchronization of the
received data. The power-down (PD) function, when enabled by asserting the PD terminal high, stops operation
of the PLL.
The TSB41AB1 supports an optional isolation barrier between itself and its LLC. When the ISO\ input terminal
is tied high, the LLC interface outputs behave normally. When the ISO\ terminal is tied low, internal differentiating
logic is enabled, and the outputs are driven such that they can be coupled through a capacitive or transformer
galvanic isolation barrier as described in Annex J of IEEE Std 1394-1995 and in IEEE 1394a-2000 (section
5.9.4) (hereinafter referred to as Annex J type isolation). To operate with TI bus holder isolation the ISO\ terminal
on the PHY must be high.
Data bits to be transmitted through the cable port are received from the LLC on two, four or eight parallel paths
(depending on the requested transmission speed) and are latched internally in the TSB41AB1 in
synchronization with the 49.152-MHz system clock. These bits are combined serially, encoded, and transmitted
at 98.304, 196.608, or 393.216 Mbits/s (referred to as S100, S200, and S400 speeds, respectively) as the
outbound data-strobe information stream. During transmission, the encoded data information is transmitted
differentially on the TPB cable pair, and the encoded strobe information is transmitted differentially on the TPA
cable pair.
During packet reception the TPA and TPB transmitters of the receiving cable port are disabled, and the receivers
for that port are enabled. The encoded data information is received on the TPA cable pair, and the encoded
strobe information is received on the TPB cable pair. The received data-strobe information is decoded to recover
the receive clock signal and the serial data bits. The serial data bits are split into two-, four-, or eight-bit parallel
streams (depending upon the indicated receive speed), resynchronized to the local 49.152-MHz system clock
and sent to the associated LLC.
Both the TPA and TPB cable interfaces incorporate differential comparators to monitor the line states during
initialization and arbitration. The outputs of these comparators are used by the internal logic to determine the
arbitration status. The TPA channel monitors the incoming cable common-mode voltage. The value of this
common-mode voltage is used during arbitration to set the speed of the next packet transmission. In addition,
the TPB channel monitors the incoming cable common-mode voltage on the TPB pair for the presence of the
remotely supplied twisted-pair bias voltage.
The TSB41AB1 provides a 1.86-V nominal bias voltage at the TPBIAS terminal for port termination. This bias
voltage, when seen through a cable by a remote receiver, indicates the presence of an active connection. This
bias voltage source must be stabilized by an external filter capacitor of 1 µF. TPBIAS is typically VDD–0.2 V when
the port is not connected to another node.
The line drivers in the TSB41AB1 operate in a high-impedance current mode, and are designed to work with
external 112-
resistors. The midpoint of the pair of resistors that is directly connected to the twisted-pair-A terminals is
connected to its corresponding TPBIAS voltage terminal. The midpoint of the pair of resistors that is directly
connected to the twisted-pair-B terminals is coupled to ground through a parallel R-C network with
recommended values of 5 k±1.0%.
When the power supply of the TSB41AB1 is off while the twisted-pair cables are connected, the TSB41AB1
transmitter and receiver circuitry presents a high impedance to the cable and does not load the TPBIAS voltage
at the other end of the cable. Fail-safe circuitry blocks any leakage path from the port back to the device power
plane.
The TESTM, SE, and SM terminals are used to set up various manufacturing test conditions. For normal
operation, the TESTM terminal should be connected to VDD through a 1-k resistor, and SM should be connected directly to ground.
Four package terminals are used as inputs to set the default value for four configuration status bits in the self-ID
packet, and are tied high through a 1-k. See Table 9 for power-class encoding. The C/LKON
terminal is used as an input to indicate that the node is a contender for either isochronous resource manager
(IRM) or for bus manager (BM).</p>
<p>The TSB41AB1 supports suspend/resume as defined in the IEEE 1394a-2000 specification. The suspend
mechanism allows pairs of directly connected ports to be placed into a low-power state (suspended state) while
maintaining a port-to-port connection between bus segments. While in the suspended state, a port is unable
to transmit or receive data transaction packets. However, a port in the suspended state is capable of detecting
connection status changes and detecting incoming TPBIAS. When the port of the TSB41AB1 is suspended,
all circuits except the band gap reference generator and bias detection circuit is powered down, resulting in
significant power savings. For additional details of suspend/resume operation see IEEE 1394a-2000. The use
of suspend/resume is recommended for new designs.</p>
<p>The port transmitter and receiver circuitry is disabled during power down (when the PD input terminal is asserted
high), during reset (when the RESET\ input terminal is asserted low), when no active cable is connected to the
port, or when controlled by the internal arbitration logic. The TPBIAS output is disabled during power down,
during reset, or when the port is disabled as commanded by the LLC.</p>
<p>The cable-not-active (CNA) output terminal (64-terminal PAP package only) is asserted high when there are
no twisted-pair cable ports receiving incoming bias (that is, they are either disconnected or suspended), and
can be used along with LPS to determine when to power down the TSB41AB1. The CNA output is not
debounced. When the PD terminal is asserted high, the CNA detection circuitry is enabled (regardless of the
previous state of the ports) and a pulldown is activated on the RESET\ terminal so as to force a reset of the
TSB41AB1 internal logic.</p>
<p>The LPS (link power status) terminal works with the C/LKON terminal to manage the power usage in the node.
The LPS signal from the LLC is used in conjunction with the LCtrl bit (see Table 1 and Table 2 in the Application
Information section) to indicate the active/power status of the LLC. The LPS signal is also used to reset, disable,
and initialize the PHY-LLC interface (the state of the PHY-LLC interface is controlled solely by the LPS input,
regardless of the state of the LCtrl bit).</p>
<p>The LPS input is considered inactive if it remains low for more than 2.6 µs and is considered active otherwise.
When the TSB41AB1 detects that LPS is inactive, it places the PHY-LLC interface into a low-power reset state
in which the CTL and D outputs are held in the logic zero state and the LREQ input is ignored; however, the
SYSCLK output remains active. If the LPS input remains low for more than 26 µs, the PHY-LLC interface is put
into a low-power disabled state in which the SYSCLK output is also held inactive. The PHY-LLC interface is also
held in the disabled state during hardware reset. The TSB41AB1 continues the necessary repeater functions required for normal network operation regardless of the state of the PHY-LLC interface. When the interface is
in the reset or disabled state and LPS is again observed active, the PHY initializes the interface and returns it
to normal operation.</p>
<p>When the PHY-LLC interface is in the low-power disabled state, the TSB41AB1 automatically enters a
low-power mode if the port is inactive (disconnected, disabled, or suspended). In this low-power mode, the
TSB41AB1 disables its internal clock generators and also disables various voltage and current reference
circuits depending on the state of the port (some reference circuitry must remain active in order to detect new
cable connections, disconnections, or incoming TPBIAS, for example). The lowest power consumption (the
ultralow-power sleep mode) is attained when the port is either disconnected, or disabled with the port interrupt
enable bit cleared. The TSB41AB1 exits the low-power mode when the LPS input is asserted high or when a
port event occurs which requires that the TSB41AB1 become active in order to respond to the event or to notify
the LLC of the event (for example, incoming bias is detected on a suspended port, a disconnection is detected
on a suspended port, a new connection is detected on a nondisabled port, etc.). The SYSCLK output becomes
active (and the PHY-LLC interface is initialized and becomes operative) within 7.3 ms after LPS is asserted high
when the TSB41AB1 is in the low-power mode.</p>
<p>The PHY uses the C/LKON terminal to notify the LLC to power up and become active. When activated, the
C/LKON signal is a square wave of approximately 163-ns period. The PHY activates the C/LKON output when
the LLC is inactive and a wake-up event occurs. The LLC is considered inactive when either the LPS input is
inactive, as described above, or the LCtrl bit is cleared to 0. A wake-up event occurs when a link-on PHY packet
addressed to this node is received, or when a PHY interrupt occurs. The PHY deasserts the C/LKON output
when the LLC becomes active (both LPS active and the LCtrl bit set to 1). The PHY also deasserts the C/LKON
output when a bus reset occurs unless a PHY interrupt condition exists which would otherwise cause C/LKON
to be active.</p></p> </div> </ti-tab-panel> </ti-tab-container> <div class=)
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