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TSB81BA3 operation

Other Parts Discussed in Thread: TSB81BA3, TSB82AA2

Hi,

I am attempting a repair on a firewire device which uses chips TSB81BA3 and tsb82aa2. The device has two firewire 800 ports and one firewire 400 port, so all ports on the TSB81BA3 are broken out to connectors.

When I plug a firewire cable into the device, which is plugged into a firewire PCI interface on a computer, the computer never detects the presence of a firewire device.  I don’t know enough about firewire to know if both the TSB81BA3 and tsb82aa2 must both be functioning correctly for the device to be detected by the computer or just the TSB81BA3 transceiver?

I have listed all of the state conditions below for the pins of the TSB81BA3. Linking a firewire port to a computer does not change the state of any of the pins below except the voltages at TPA/B (my biggest suspicion something is not working properly). The TPA+/- are pulled low to 0.07V and TPB+/- pins are presented with 3.3V from the computer which is pulled down to 0.14V when the cable is connected.

PLLVSS and DVDD-Core voltages are correct

XI=98.304MHz VOH and VOL within correct range

PD=0

BMODE=1

TPA+/- 1.71V

R0-R1 = 6.37K

DS0=1k to GND

DS1=220r to GND

TESTM=1k to Vdd

TESTW=1k to Vdd

SE=1k to GND

SM=1k to GND

PC0=GND

PC1=GND

PC2=GND

CTL0=0

CTL1=0

PCLK=0 (this should be active since 0.22uS and 2.4uS shorter than 26uS LPS_DISABLE time?)

LCLK=0

LKON/DS2=0

RSVD=98.304MHz 25mV pk-pk (should be 3.3V pk?)

CNA=1  (This should change when linked to a computer firewire PCI card?)

CPS=GND

PD=0

RESETZ=1

LREQ=0

PINT=0

D0-7=0

LPS=0.23uS on, 0.22uS off

       =2.4uS on, 2.4uS off

(LPS input sometimes 1x and other times, 10x frequency)

I would appreciate any help. I think the parts in bold above show a faulty chip or something else? The chip is new so should be ok.

Kind Regards,

  • Hello,

    Are the TSB82AA2 and the TSB81BA3 recognized by the operating system?
    Both devices must be operating in order for the PC to enumerate a 1394 device.
    Can you get the schematic?

    If the TSB81BA3 is powered up, you should be able to connect two 1394 devices on two of its ports and have those two devices communicate each other, even if the PC is not running, this will tell us the TSB81BA3 is working properly.

    Regards
  • Hi,

    The computer/operating system never detects the presence of a firewire device. The TSB82AA2 interfaces with an FPGA and I cannot be sure at the moment if the FPGA is working. If both TSB82AA2 and TSB81BA3 are working but FPGA is damaged/not sending any data to the TSB82AA2, would the operating system still enumerate an "unknown device" on the firewire port?

    Unfortunately the manufacturer will not release the schematics.

    How would I know the devices were communicating with each other without a PC?
    It would be better to chain another device through it to the PC and see if it was detected?
    I.e. firewire hard drive/camera ----> a FW400/800 port on faulty device ----> PC
    If the chip is working the PC should be able to connect to a hard drive etc through the test device?

    Thanks

  • Hello,

    Is the device manager showing the "1394 OHCI Host Controller" ?
    The TSB82AA2 requires to be communicating with the PC in order to know whether it is working properly or not.
    You can test the TSB81BA3 without a PC connection, just power it up, connect another PC to one of its 1394 ports and connect a 1394 device as well on another port, the PC should "see" the 1394 device through the TSB81BA3.

    Regards
  • Hi,

    Device manager does not show anything at all. 

    "You can test the TSB81BA3 without a PC connection, just power it up, connect another PC"

    This doesn't make any sense??

    I assume you are saying without a connection to the controller on the faulty device and just use the transceiver on the faulty device as a relay buffer for another device?

    i.e external hd --> faulty device --> PC ?

    Let me know if this is correct and I will test.

    Thanks

  • Hello,

    Sorry for the delay, please see attached picture, as long as the TSB81BA3 is powered up it should act as a repeater no matter that the TSB82AA2 is not working.

    Regards

  • Hi,

    I have managed to test another 1394 device and it is working as in your diagram. 

    Does this mean the TSB81BA3 is certainly working?

    Thanks

  • It means that the TSB81BA3 works. And a 2 MHz signal on the LPS pin shows that the TSB82AA2 has been configured and initialized over the PCI bus.