Developing TDC1000 hardware board

Ahmed Kamel

Other Parts Discussed in Thread: TDC1000, TDC7200

Hello, i am working with ultrasonic water flow sensor and developing my own PCB to interface the sensor with TDC1000. I have a misunderstanding in TDC1000 active channel definition; to measure the water flow rate i should use mode 2 for measurement, which define channel 1 as TX1/RX1 and channel 2 as TX2/RX2. Does TDC1000 have the ability to internally change the channel definition for the different measuring mode or should i connect it myself by the hardware ?What is the right channel connection to measure in mode 2 ?

Thank you

over 9 years ago

0 Matthew Minasi over 9 years ago

TI__Expert 4725 points

Ahmed,
The TX/RX pairs cannot be reassigned in any mode. So in Mode 2 Channel 1 refers to the TX1/RX1 pins as a functioning pair. So while Channel 1 is active transmission will occur on the TX1 pin and the LNA will be listening on the RX1 pin. On the next measurement cycle if the the CH_SWP bit is asserted the next active channel will be channel 2 which is the TX2/RX2 pair.

for details refer to datasheet section 8.4 Table 3.

Flow measurements require bidirectional TOF measuements. As shown in Table 3 which TX/RX pair are associated to what TOF_measuremnt_mode is in use as defined in Table 3. In general you should be using Mode 2. In Mode 2 which is the active channel is defined by the state machine and if the CH_SWP bit is asserted.

-Regards,

0 Ahmed Kamel over 9 years ago in reply to Matthew Minasi

Intellectual 935 points

Ok, but regarding page 34 in the TDC7200 datasheet, TX1/RX2 forms channel B and TX2/RX1 forms channel A for flow metering application.

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Developing TDC1000 hardware board