topic Re: TWR-K70F120M Kit cpu and two UARTs in Kinetis Microcontrollers

TWR-K70F120M Kit cpu and two UARTs

jum — Mon, 02 Feb 2015 14:53:38 GMT

Plan to use UART with TWR-K70 Kit for application. Would prefer cpu UART0.
One UART (cpu UART2, cpu SCH signals PTE16/PTE17, ELEV pins A44/A43 via R116/R115) is routed to TWR-SER board and should be used for debug/conio purpose.
I see one other UART on cpu board tower pins: Cpu UART3, cpu SCH signals PTF8/PTF7, ELEV pins A42/A41 via R135/R134. R135 and R134 have attribut "DNP" (do not place).

1. So to get cpu UART3 Rx/Tx to work: Simply have to place these '0 ohm resistors'/wires ?

2. As PTF8/PTF7 also are connected to 'LCD_D4/LCD_D3': May still use UART3 with active LCD board mounted?

3. See Cpu UART0 (preferred) connected to cpu SCH signals PTF18/PTF17. These are connected to LCD_D14/LCD_D13. Can use them with LCD dismounted?

4. Any other suggestion for second/application UART on this kit?

Best regards, Juergen.

Re: TWR-K70F120M Kit cpu and two UARTs

Hui_Ma — Tue, 03 Feb 2015 03:26:02 GMT

1. If customer want to use UART3 at PTF7/PTF8 pins, it need to use TWR-SER2 board instead of TWR-SER board.

2. The PTF7/PTF8 pin with multiple-function, which could affect the LCD display when using both pin for UART communication.

3. Both TWR-SER and TWR-SER2 boards don't provide RS232 PHY connection with PTF17/PTF18 pin, there couldn't use PTF17/PTF18 for UART function.

4. Based on previous analysis, customer could use PTF7/PTF8 of K70 UART3 with TWR-SER2 board with LCD board unmounted.

Wish it helps.

About TWR-SER2 board info, please check below link:

Enhanced Serial (Dual Ethernet, High-Speed US|Freescale

Have a great day,
best regards,

Ma Hui

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Re: TWR-K70F120M Kit cpu and two UARTs

jum — Tue, 03 Feb 2015 07:36:02 GMT

Ok, have not been exact enough in description.
Want to build second application UART port onto a TWR-PROTO board. This second UART is TTL-UART, so do not need RS-232 PHY. TWR is populated with TWR-K70 cpu board, TWR-SER board and TWR-PROTO board. May like to have TWR-LCD too, but can live without it. Can omit TWR-SER, as 'printf' could be catched via USB too.

Need advice, which UART port of cpu board to use (would prefer UART0).

Summary for TWR-K70F120M cpu board (please tell, if wrong):

There are 4 possible UART(-Rx-Tx) default pin pairs on TWR-ELEV boards (I call them "twre_UARTx" in contrast to "cpu_UARTx"):

"twre_UART0" is connected to "cpu_UART2"

"twre_UART1" is connected to "cpu_UART3" (if 0 Ohm bridges R134/R135 would be placed)

"twer_UART2" is not connected to cpu

"twer_UART3" is not connected to cpu.

Prefer using "cpu_UART0". Possible TWR-ELEV pins for "cpu_UART0_RX/TX" are:

PTF17/PTF18

PTA1/PTA2

PTA15/PTA16

PTB16/PTB17

PTD6/PTD7.

Think that PTF17/PTF18 (secondary connector D53/D54) is best to catch "cpu_UART0_RX/TX" on a TWR-PROTO board.
Seems to have lowest conflict potential with other TWR boards. Do you agree?

Best regards, Juergen.

Re: TWR-K70F120M Kit cpu and two UARTs

Hui_Ma — Wed, 04 Feb 2015 08:52:41 GMT

Hi Juergen,

For K70 product provide Graphic LCD controller, if customer consider to use TWR-LCD-RGB board?

About TWR-LCD-RGB info, please check below link:

http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=TWR-LCD-RGB&tid=m32TWR

If using TWR-LDC baord, the PTF17/PTF18 is prefer pins for K70 UART0.

If using TWR-LCD-RGB board, Customer could consider to use PTA14/PTA15 or PTB16/PTB17 or PTD6/PTD7 as K70 UART0 pins.

Wish it helps.

Have a great day,
best regards,

Ma Hui