https://community.nxp.com/t5/Other-NXP-Products/SC16IS750-problem-to-verify-TX-RX-functionality/m-p/1222304#M10360 <P>Here I attached the SPI reference code,hope this could help you!</P> <P>&nbsp;</P> Thu, 28 Jan 2021 02:07:17 GMT guoweisun 2021-01-28T02:07:17Z https://community.nxp.com/t5/Other-NXP-Products/SC16IS750-problem-to-verify-TX-RX-functionality/m-p/1218405#M10306 <P>Hi</P><P>I have a simple project with this IC.</P><P>I just configured the product to work as I2C - UART.</P><P>But when I write in the THR register, I expect the TXLVL register needs to show some number related to number of spaces available. But this register is always with the same number.</P><P>I am using a Raspberry to send the I2C commands, and I read all related documentation and follow the order of the commands this forum suggests but I am not having success.</P><DIV><DIV><SPAN>"""</SPAN></DIV><DIV><SPAN>self.bus.write_byte_data(self.DEVICE_ADDRESS, LCR, 0x80)</SPAN></DIV><DIV>&nbsp;</DIV><DIV><SPAN># Set DLL</SPAN></DIV><DIV><SPAN>self</SPAN><SPAN>.bus.write_byte_data(</SPAN><SPAN>self</SPAN><SPAN>.DEVICE_ADDRESS, DLL, </SPAN><SPAN>0x</SPAN><SPAN>78</SPAN><SPAN>)</SPAN></DIV><BR /><DIV><SPAN># Set DLH</SPAN></DIV><DIV><SPAN>self</SPAN><SPAN>.bus.write_byte_data(</SPAN><SPAN>self</SPAN><SPAN>.DEVICE_ADDRESS, DLM, </SPAN><SPAN>0x</SPAN><SPAN>00</SPAN><SPAN>)</SPAN></DIV><BR /><SPAN>print</SPAN><SPAN>(</SPAN><SPAN>"Set 0xBF"</SPAN><SPAN>)</SPAN><DIV><SPAN>self</SPAN><SPAN>.bus.write_byte_data(</SPAN><SPAN>self</SPAN><SPAN>.DEVICE_ADDRESS, LCR, </SPAN><SPAN>0x</SPAN><SPAN>BF</SPAN><SPAN>)</SPAN></DIV><BR /><DIV><SPAN># EFR only can be accessed with LCR = 0xBF</SPAN></DIV><DIV><SPAN># EFR[4] --&gt; enable enhanced functions </SPAN></DIV><DIV><SPAN>self</SPAN><SPAN>.bus.write_byte_data(</SPAN><SPAN>self</SPAN><SPAN>.DEVICE_ADDRESS, EFR, </SPAN><SPAN>0x</SPAN><SPAN>10</SPAN><SPAN>)</SPAN></DIV><DIV>&nbsp;</DIV><DIV><SPAN># 8 data bit, 1 stop bit, no parity</SPAN></DIV><DIV><SPAN>self</SPAN><SPAN>.bus.write_byte_data(</SPAN><SPAN>self</SPAN><SPAN>.DEVICE_ADDRESS, LCR, </SPAN><SPAN>0x</SPAN><SPAN>03</SPAN><SPAN>)</SPAN></DIV><BR /><DIV><SPAN># FCR: 0 0 1 0 0 1 1 1</SPAN></DIV><DIV><SPAN>self</SPAN><SPAN>.bus.write_byte_data(</SPAN><SPAN>self</SPAN><SPAN>.DEVICE_ADDRESS, FCR, </SPAN><SPAN>0x</SPAN><SPAN>27</SPAN><SPAN>)</SPAN></DIV></DIV><P>"""</P><P>Log of execution:</P><P>Line Status LSR (hex): 0x60<BR />Modem status MSR (hex): 0x0<BR />TXLVL (hex): 0x40<BR />RXLVL (hex): 0x0</P><P>Writing DATA to THR: 0xfa<BR />Reading DATA (hex) from RHR:&nbsp; 0x19<BR />Line Status LSR (hex): 0x60<BR />Modem status MSR (hex): 0x0<BR />TXLVL (hex): 0x40<BR />RXLVL (hex): 0x0</P><P>Writing DATA to THR: 0xfb<BR />Reading DATA (hex) from RHR:&nbsp; 0x19<BR />Line Status LSR (hex): 0x60<BR />Modem status MSR (hex): 0x0<BR />TXLVL (hex): 0x40<BR />RXLVL (hex): 0x0</P><P>&nbsp;</P><P>As you see, there is no changes in the Status or Tx/Rrx registers.</P><P>Do you have some idea of how to debug this?</P><P>I saw TX pin is always high. But the configuration is OK.</P><P>Regards</P><P>&nbsp;</P> Thu, 21 Jan 2021 02:14:24 GMT https://community.nxp.com/t5/Other-NXP-Products/SC16IS750-problem-to-verify-TX-RX-functionality/m-p/1218405#M10306 jedward1977 2021-01-21T02:14:24Z https://community.nxp.com/t5/Other-NXP-Products/SC16IS750-problem-to-verify-TX-RX-functionality/m-p/1222304#M10360 <P>Here I attached the SPI reference code,hope this could help you!</P> <P>&nbsp;</P> Thu, 28 Jan 2021 02:07:17 GMT https://community.nxp.com/t5/Other-NXP-Products/SC16IS750-problem-to-verify-TX-RX-functionality/m-p/1222304#M10360 guoweisun 2021-01-28T02:07:17Z