Dear Community,
I use the transceiver MC33664A. I wanted to test whether the transceiver converts the MOSI signal to TPL correctly. I threw something together as a MOSI data frame. However the TPL signal doens´t look as it should.
green - CSB
yellow - TPL (RTDX)
blue - MOSI
purple - SCLK
Do you have any ideas as to what thhis could be? Could it be because the enable pin is at 5V?
best regards,
Patrick
Dear Patrick,
thank you for the scope. It looks, that there is not any message passing on the RDTX+, RDTX- pins. It looks only as a noise. Please share your schematic with voltage levels and part values.
With Best Regards,
Jozef
Dear Patrick,
thank you for the schematic and closer look to the scope. The schematic is correct. Now when you have sent me the closer look to the scope, it resembles the TPL signal. But you need to measure it on both RDTX+ and RDTX- pin.
For the TPL message structure, please refer to the section 2.3 in the AN5271 attached.
You can use our TPL sniffer tool KIT-TPLSNIFEVB to decode the TPL signal. And you also need a logic analyzer. Please refer to the UM11650.
Regarding the voltage on the EN pin, if you have applied 3.3V to VIO pin, you can damage the MC33664 with 5V to EN pin. The maximum allowed voltage on the EN pin is VIO+0.3V. Please refer to the Table 4. in the MC33664 datasheet.
With Best Regards,
Jozef
