Other Parts Discussed in Thread: TMS320C6657, TMS320C6748, SN74CBTLV3251, SN74ALVC245, SN74AXC8T245
Hi
I have a question about converting the voltage of a uPP signal using TXS0108E.
The TXS0108E was used as a voltage translator for uPP interface between the TMS320C6657 and TMS320C6748.
SN74ALVC245 was used for the buffer. The SN74CBTLV3251 is used to branch control signals to uPP interface with five TMS320C6748s.
The A channel is TX and the B channel is RX.
Based on the TMS320C6657, TX has no problem, but RX has a problem.
The RX signal was checked and the signal was distorted.
Number 1(Yellow) is the uPP_CH0_ENABLE signal of TMS320C6748, number 2(Green) is the uPP_CH1_ENABLE signal of TMS320C6657.
For the test, the voltage was checked without connecting to side B of TXS0108E as shown below.
Number 1(Yellow) is the side B, number 2(Green) is side A.
1.4V is measured at A of TXS0108E. 3.3V is measured at B of the TXS0108E.
A side should be 0V. Because uPP is set to RX. And I don't know why 1.4V is measured.
If OE is set low, both A and B are measured at 0V.
Setting the uPP to TX on the TMS320C6657 is OK, but setting it to RX has a problem.
Is there a hardware problem when uPP is set to RX and connected to TXS0108E?
If there is a problem, please recommend a solution or another IC.
Thank you and regards.
