The Texas Instruments TSB43AB22A device is an integrated 1394a-2000 OHCI PHY/link-layer controller (LLC) device that is fully compliant with the _PCI Local Bus Specification_, the _PCI Bus Power Management Interface Specification_, IEEE Std 1394-1995, IEEE Std 1394a-2000, and the _1394 Open Host Controller Interface Specification_. It is capable of transferring data between the 33-MHz PCI bus and the 1394 bus at 100M bits/s, 200M bits/s, and 400M bits/s. The TSB43AB22A device provides two 1394 ports that have separate cable bias (TPBIAS). The TSB43AB22A device also supports the IEEE Std 1394a-2000 power-down features for battery-operated applications and arbitration enhancements.
As required by the _1394 Open Host Controller Interface Specification_ (OHCI) and IEEE Std 1394a-2000, internal control registers are memory-mapped and nonprefetchable. The PCI configuration header is accessed through configuration cycles specified by PCI, and it provides plug-and-play (PnP) compatibility. Furthermore, the TSB43AB22A device is compliant with the _PCI Bus Power Management Interface Specification_ as specified by the _PC 2001 Design Guide_ requirements. The TSB43AB22A device supports the D0, D1, D2, and D3 power states.
The TSB43AB22A design provides PCI bus master bursting, and it is capable of transferring a cacheline of data at 132M bytes/s after connection to the memory controller. Because PCI latency can be large, deep FIFOs are provided to buffer the 1394 data.
The TSB43AB22A device provides physical write posting buffers and a highly-tuned physical data path for SBP-2 performance. The TSB43AB22A device also provides multiple isochronous contexts, multiple cacheline burst transfers, advanced internal arbitration, and bus-holding buffers.
An advanced CMOS process achieves low power consumption and allows the TSB43AB22A device to operate at PCI clock rates up to 33 MHz.
The TSB43AB22A PHY-layer provides the digital and analog transceiver functions needed to implement a two-port node in a cable-based 1394 network. Each cable port incorporates two differential line transceivers. The transceivers include circuitry to monitor the line conditions as needed for determining connection status, for initialization and arbitration, and for packet reception and transmission.
The TSB43AB22A PHY-layer requires only an external 24.576-MHz crystal as a reference for the cable ports. 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 that control transmission of the outbound encoded strobe and data information. A 49.152-MHz clock signal is supplied to the integrated LLC for synchronization and is used for resynchronization of the received data.
Data bits to be transmitted through the cable ports are received from the integrated LLC and are latched internally in synchronization with the 49.152-MHz system clock. These bits are combined serially, encoded, and transmitted at 98.304M, 196.608M, or 393.216M bits/s (referred to as S100, S200, or S400 speeds, respectively) as the outbound data-strobe information stream. During transmission, the encoded data information is transmitted differentially on the twisted-pair B (TPB) cable pair(s), and the encoded strobe information is transmitted differentially on the twisted-pair A (TPA) cable pair(s).
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 resynchronized to the local 49.152-MHz system clock and sent to the integrated LLC. The received data is also transmitted (repeated) on the other active (connected) cable ports.
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 TSB43AB22A device provides a 1.86-V nominal bias voltage at the TPBIAS terminal for port termination. The PHY layer contains two independent TPBIAS circuits. 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 1.0 uF.
The line drivers in the TSB43AB22A device operate in a high-impedance current mode and are designed to work with external 112- cable impedance. One network is provided at each end of a twisted-pair cable. Each network is composed of a pair of series-connected 56- resistors. The midpoint of the pair of resistors that is directly connected to the TPA terminals is connected to its corresponding TPBIAS voltage terminal. The midpoint of the pair of resistors that is directly connected to the TPB terminals is coupled to ground through a parallel R-C network with recommended values of 5 k and 220 pF. The values of the external line-termination resistors are designed to meet the standard specifications when connected in parallel with the internal receiver circuits. An external resistor connected between the R0 and R1 terminals sets the driver output current and other internal operating currents. This current-setting resistor has a value of 6.34 k ±1%.
When the power supply of the TSB43AB22A device is off and the twisted-pair cables are connected, the TSB43AB22A transmitter and receiver circuitry present a high impedance to the cable and do not load the TPBIAS voltage at the other end of the cable.
When the device is in a low-power state (for example, D2 or D3) the TSB43AB22A device automatically enters a low-power mode if all ports are inactive (disconnected, disabled, or suspended). In this low-power mode, the TSB43AB22A device disables its internal clock generators and also disables various voltage and current reference circuits, depending on the state of the ports (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 all ports are either disconnected or disabled with the port interrupt enable bit cleared.
The TSB43AB22A device exits the low-power mode when bit 19 (LPS) in the host controller control register at OHCI offset 50h/54h (see Section 4.16, _Host Controller Control Register_) is set to 1 or when a port event occurs which requires that the TSB43AB22A device to 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, or a new connection is detected on a nondisabled port). When the TSB43AB22A device is in the low-power mode, the internal 49.153-MHz clock becomes active (and the integrated PHY layer becomes operative) within 2 ms after bit 19 (LPS) in the host controller control register at OHCI offset 50h/54h (see Section 4.16, _Host Controller Control Register_) is set to 1.
The TSB43AB22A device supports hardware enhancements to better support digital video (DV) and MPEG data stream reception and transmission. These enhancements are enabled through the isochronous receive digital video enhancements register at OHCI offset A88h (see Chapter 5, _TI Extension Registers_). The enhancements include automatic timestamp insertion for transmitted DV and MPEG-formatted streams and common isochronous packet (CIP) header stripping for received DV streams.
The CIP format is defined by the IEC 61883-1:1998 specification. The enhancements to the isochronous data contexts are implemented as hardware support for the synchronization timestamp for both DV and MPEG CIP formats. The TSB43AB22A device supports modification of the synchronization timestamp field to ensure that the value inserted via software is not stalethat is, the value is less than the current cycle timer when the packet is transmitted.
Fully compliant with provisions of IEEE Std 1394-1995 for a high-performance serial bus and IEEE Std 1394a-2000
Fully interoperable with FireWire and i.LINK implementations of IEEE Std 1394
Compliant with Intel _Mobile Power Guideline 2000_
Full IEEE Std 1394a-2000 support includes: connection debounce, arbitrated short reset, multispeed concatenation, arbitration acceleration, fly-by concatenation, and port disable/suspend/resume
Power-down features to conserve energy in battery-powered applications include: automatic device power down during suspend, PCI power management for link-layer, and inactive ports powered down
Ultralow-power sleep mode
Two IEEE Std 1394a-2000 fully compliant cable ports at 100M bits/s, 200M bits/s, and 400M bits/s
Cable ports monitor line conditions for active connection to remote node
Cable power presence monitoring
Separate cable bias (TPBIAS) for each port
1.8-V core logic with universal PCI interfaces compatible with 3.3-V and 5-V PCI signaling environments
Physical write posting of up to three outstanding transactions
PCI burst transfers and deep FIFOs to tolerate large host latency
(PCI_CLKRUN)\ protocol
External cycle timer control for customized synchronization
Extended resume signaling for compatibility with legacy DV components
PHY-Link logic performs system initialization and arbitration functions
PHY-Link encode and decode functions included for data-strobe bit level encoding
PHY-Link incoming data resynchronized to local clock
Low-cost 24.576-MHz crystal provides transmit and receive data at 100M bits/s, 200M bits/s, and 400M bits/s
Node power class information signaling for system power management
Serial ROM interface supports 2-wire serial EEPROM devices
Two general-purpose I/Os
Register bits give software control of contender bit, power class bits, link active control bit, and IEEE Std 1394a-2000 features
Fabricated in advanced low-power CMOS process
PCI and CardBus register support
Isochronous receive dual-buffer mode
Out-of-order pipelining for asynchronous transmit requests
Register access fail interrupt when the PHY SCLK is not active
PCI power-management D0, D1, D2, and D3 power states
Initial bandwidth available and initial channels available registers
(PME)\ support per _1394 Open Host Controller Interface Specification_
Implements technology covered by one or more patents of Apple Computer, Incorporated and SGS Thompson, Limited.
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