TSB12LV41A Datasheet, PDF (85/199 Pages) Texas Instruments – IEEE 1394-1995 Link-Layer Controller for Consumer Applications

BDOCLK
tsu2
BDI(0–7)^{ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ td3}
BDIF(0–2)_{ÎÎÎÎÎÎÎÎÎÎÎÎÎ}
BDIEN
th2
td3
ÎÎÎÎÎÎ
ÎÎÎ
BDOEN
td2
td2
BDOAVAIL
NAME
MIN
(ns)
tsu2
12
td2
td3
th2
0
MAX
(ns)
6
6
DESCRIPTION
Setup time to rising edge of clock
Delay time from rising edge of clock
Delay time from rising edge of clock
Hold time from rising edge of clock
Figure 4–17. Critical Timing for Read Operations in Bidirectional Mode
4.2.2.3 Bidirectional Interleave Timing
Figure 4–18 shows the read and write interleave operation in bidirectional mode. BDICLK is used for writes
to the bulky data interface and BDOCLK is used for reads form the bulky data interface.
(BDIO[7–0]_OUT and BDIO[7–0]_IN are physically the same bus. They are named so for ease of readability.
The same is true for BDIF[2–0].)
BDOAVAIL active indicates that a packet is available in the receive FIFO. The application activates BDIEN
(enabling read and write operations) and drives BDOEN high, indicating a read. The TSB12LV41A output
the first byte of MPEG2/DSS/Asynchronous/Isochronous data. The TSB12LV41A indicates the data’s
format by driving values on the BDIF format bus.
Next the application performs a write operation by driving BDOEN low while keeping BDIEN active. The
application simultaneously drives BDIO[7–0] with the first byte of the data packet. BDIF[2–0] is also driven
by the application to indicate the data packet format.
This sequence continues with a read followed immediately by a write until the hardware indicates busy by
activating BDIBUSY. This suspends write operations to the bulky data interface. However, read operations
continue and take the full bandwidth of the interface. After byte 7 is read, the application suspends the read
by deactivating BDIEN. At this point, both the read and write are suspended and the buses are in a high
impedance state. BDIBUSY is deactivated indicating that data can continue to be written to the transmit
FIFO. The application activates BDIEN and drives BDOEN low to indicate another write to the bulky data
interface. Another read follows this.
4–17