TLC32047C Datasheet, PDF (31/61 Pages) Texas Instruments – Wide-Band Analog Interface Circuit

FSX
FSR
t1
Transmit Conversion Period
Receive Conversion
Period A
Receive Conversion
Period B
Figure 2–5. More Than One Receive Frame Sync Between Two Transmit Frame Syncs
2.22 More Than One Transmit Frame Sync Occurring Between Two Receive
Frame Syncs – Asynchronous Operation
When incrementally adjusting the conversion period via the A + A′ or A – A′ register options, a specific
protocol must be followed. For both transmit and receive conversion periods, the incremental conversion
period adjustment is performed near the end of the conversion period. The command to use the incremental
conversion period adjust options is sent to the AIC during an FSX frame sync. The ongoing transmit
conversion period is then adjusted. However, three possibilities exist for the receive conversion period
adjustment as shown in Figure 2–6. When the adjustment command is issued during transmit conversion
period A, receive conversion period A is adjusted if there is sufficient time between t₁ and t₂. If there is not
sufficient time between t₁ and t₂, receive conversion period B is adjusted. The third option is that the receive
portion of an adjustment command can be ignored if the adjustment command is sent during a receive
conversion period, which is adjusted due to a prior adjustment command. For example, if adjustment
commands are issued during transmit conversion periods A, B, and C, the first two commands may cause
receive conversion periods A and B to be adjusted, while the third receive adjustment command is ignored.
The third adjustment command is ignored since it was issued during receive conversion period B, which
already is adjusted via the transmit conversion period B adjustment command.
t1
FSX
FSR
Transmit
Conversion
Period A
t2
Transmit
Conversion
Period B
Transmit
Conversion
Period C
Receive Conversion Period A
Receive Conversion Period B
Figure 2–6. More Than One Transmit Frame Sync Between Two Receive Frame Syncs
2.23 More than One Set of Primary and Secondary DX Serial Communications
Occurring Between Two Receive Frame Syncs (See DX Serial Data Word
Format section) – Asynchronous Operation
The TA, TA′, TB, and control register information that is transmitted in the secondary communication is
accepted and applied during the ongoing transmit conversion period. If there is sufficient time between t₁
and t₂, the TA, RA′, and RB register information, sent during transmit conversion period A, is applied to
receive conversion period A. Otherwise, this information is applied during receive conversion period B. If
RA, RA′, and RB register information has been received and is being applied during an ongoing conversion
period, any subsequent RA, RA′, or RB information received during this receive conversion period is
disregarded. See Figure 2–7.
2–13