LPUART instance FRDM-KE16Z

[malina]

Hi! I am using FRDM-KE16Z for a project. I tried to use LPUART0 and LPUART1 (LPUART2 is already used for another purpose), but I cannot find the proper pin on Arduino outputs. I only need the RX pin for LPUART. I already saw that the LPUART0_RX is PTB0 and LPUART1_RX is PTC6, but when I connect the wire and try to establish the connection, it gets a framing error. I tested my code on LPUART2, and it works.

[Pavel_Hernandez]

Hello, my name is Pavel, and I will be supporting your case, I recommend reviewing the schematic of this board the UART0 is not available, because is used by the MK20 and routed on the board, that why is not available on the Arduino pins.

Pavel_Hernandez_0-1710549711915.png

But maybe you could use these other pins.

Pavel_Hernandez_1-1710549842607.png

Pavel_Hernandez_2-1710549865162.png

Best regards,
Pavel

[malina]

Unfortunately, I am already using the PTA3 pin as SDA for I2C.

[Pavel_Hernandez]

Hello, I am afraid is not possible to use those pins that you want, because are not available.

Best regards,
Pavel

[malina]

I tried to use PTC6 as RX for LPUART1 by switching the R30 jumper resistance to R31 as shown in the schematics. 

malina_0-1710939834103.png

It doesn't work. The pinout on the backwards of the development board and the schematics don't match. For example, on J1 in the schematics is PTC6 and on the backward of my development board is PTC8(which doesn't exist in the schematics). 

malina_1-1710939872163.png

malina_2-1710940445181.jpeg

[Pavel_Hernandez]

Hello, oh! you are right, but I checked the output of the R31 and has continuity with pin 2 of J1, there is an error on the silkscreen.

Best regards,
Pavel

[malina]

Still...it doesn't solve the problem. The pin 2 of J1 (PTC6) doesn't work as RX for LPUART1, as it should.

[Pavel_Hernandez]

Hello, I reviewed the Schematic again could you try without the pull-up resistor? If this does not work, I will test it on my side.

Pavel_Hernandez_0-1711061539499.png

Best regards,
Pavel