TLC32047C Datasheet, PDF (24/61 Pages) Texas Instruments – Wide-Band Analog Interface Circuit

2.9.2 Two 8-Bit Bytes (Byte Mode)
The serial port interfaces directly with the serial port of the TMS320C17 and communicates in two 8-bit
bytes. The operation sequence is as follows:
1. FSX and FSR are brought low.
2. One 8-bit word is transmitted and one 8-bit word is received.
3. EODX and EODR are brought low.
4. FSX and FSR emit positive frame-sync pulses that are four shift clock cycles wide.
5. One 8-bit byte is transmitted and one 8-bit byte is received.
6. FSX and FSR are brought high.
7. EODX and EODR are brought high.
2.9.3 Synchronous Operating Frequencies
The synchronous operating frequencies are determined by the following equations.
Switched capacitor filter (SCF) frequencies (see Figure 2–1):
Low- pass SCF clock frequency
ń ń + (D A and A D channels)
master clock frequency
T(A) 2
ń + ń High- pass SCF clock frequency (A D channel) A D conversion frequency
ń ń + ^-
Conversion frequency (A D and D A channels)
Low pass SCF clock frequency
T(B)
+ master clock frequency
T(A) 2 T(B)
NOTE: T(A), T(B), R(A), and R(B) are the contents of the TA, TB, RA, and RB registers, respectively.
2.10 Asynchronous Operation
When the transmit and the receive sections are operated asynchronously, the low-pass and band-pass filter
clocks are independently generated from the master clock. The D/A and the A/D conversion timing is also
determined independently.
D/A timing is set by the counters and registers described in synchronous operation, but the RA and RB
registers are substituted for the TA and TB registers to determine the A/D channel sample rate and the A/D
path switched-capacitor filter frequencies. Asynchronous operation is selected by control register bit D5
being zero.
2.10.1 One 16-Bit Word (Word Mode)
The serial port interfaces directly with the serial ports of the TMS32020, TMS320C25, and TMS320C30 and
communicates with 16-bit word formats. The operation sequence is as follows:
1. FSX or FSR are brought low by the TLC32047 AIC.
2. One 16-bit word is transmitted or one 16-bit word is received.
3. FSX or FSR are brought high.
4. EODX or EODR emit low-going pulses one shift clock wide. EODX and EODR are valid in either
the word or byte mode only.
2.10.2 Two 8-Bit Bytes (Byte Mode)
The serial port interfaces directly with the serial port of the TMS320C17 and communicates in two 8-bit
bytes. The operating sequence is as follows:
1. FSX or FSR are brought low by the TLC32047 AIC.
2. One byte is transmitted or received.
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