topic Re: how to set EVEN-7BIT-1 STOP BIT SETTING FOR FRDMK64 in Kinetis Software Development Kit

how to set EVEN-7BIT-1 STOP BIT SETTING FOR FRDMK64

sudhakarp — Fri, 18 Sep 2015 04:05:10 GMT

HI,

I am using FRDMK64f120 controller, KDS2.0 and KSDK 1.1.0 example am using. i tried to set

following setting in hello example project but its not working. how to solve this problem.

E-Even parity, 7,8-bit 1,2-stop bit

1)E71

2)E82

3)O71

4)N82

its working fine with NOne ,8bit and 1 stop bit. but i need above setting how to solve this problem.

please give some idea.

regards,

sudhakar p

Re: how to set EVEN-7BIT-1 STOP BIT SETTING FOR FRDMK64

isaacavila — Mon, 02 Nov 2020 13:23:23 GMT

Hello Sudhakar,

First of all, you should understand data format in UART module, lets suppose LSB is sent first.

If you select 8-bit data format and enable parity bit, 7 are reserved for data and the one (MSB) is reserved for parity (either odd or even) as shown below:

Internal hardware checks parity bit according to parity mode selected (even or odd) and it sets/clears the flag if there is a parity error on received character, so, if you are using this mode, you should read 8 bits and then mask the 8th bit to discard parity bit (hardware already checks for parity error):

uint8_t received_data, parity, real_data;
UART_HAL_Getchar(base, &received_data);
real_data = received_data & 0x7F;
parity = (received_data & 0x80) >> 7;

When you try to use 8 data bits and add an aditional parity bit, you should enable 9 bit transmission (8 data + 1 parity) and data format is:

In this case, we need to read 9 bits (8 bits are read in UARTx_D register and MSB bit is read in UARTx_C3[R8] flag),so, it is neccesary to read C3 before reading D register. Again, internal hardware checks for parity bit and sets/clears correspoding flag if there is a parity error. For KSDK 1.2.0 drivers, there is a function that allows user to read/write 9 bits:

UART_HAL_Getchar9(base, &data_16_bits);

Current UART driver in KSDK does use 8 bit data format with no parity, so, you should consider masking the MSB bit if parity is enabled.

Attach you can find a basic project using UART_HAL functions that KSDK provides in order to read 8 or 9 bits. I check both versions and it works well (even though i had problems on 8 bit format because Putty does not uses 7 data + 1 parity bit but if you apply this technique when communicating two boards you will see that communication is stablished correctly.)

I hope this can serve as guidance in order to create your own driver.

Note: For Stop bits, it should be no problem when chaning from 1 to 2, due these bits are internally managed.

Best Regards,

Isaac

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Re: how to set EVEN-7BIT-1 STOP BIT SETTING FOR FRDMK64

sudhakarp — Tue, 06 Oct 2015 13:01:21 GMT

hi,

still i have same problem.

actually i configured like this for 7E1-(7bit ,even,one stop bit)

uart_user_config_t uartConfig = {

.bitCountPerChar = kUart8BitsPerChar,

.parityMode = kUartParityEven,

.stopBitCount = kUartOneStopBit,

.baudRate = BOARD_DEBUG_UART_BAUD

};

its only displaying some character correctly. some character am getting junk value [example:"C"]. why?

and also you told Stop bit not depends on number of bits per char. i tried 8N2 this one also not working.

can you give some other solution for 7bit data transfer with parity..?

and also i need all combination

1)E71

2)E82

3)O71

4)N82

regards,

sudhakar p

Re: how to set EVEN-7BIT-1 STOP BIT SETTING FOR FRDMK64

sudhakarp — Tue, 06 Oct 2015 13:11:14 GMT

hi,

if i configure 9bit for(7E1 and 8E1) without junk i can able to receive.But i sent large data 1k am getting junk value. 2-stop bit condition was not working at all.

without parity also 2-stop bit not working why?

regards,

sudhakar p

Re: how to set EVEN-7BIT-1 STOP BIT SETTING FOR FRDMK64

sudhakarp — Wed, 07 Oct 2015 12:17:39 GMT

hi,

i tried UART1 port with 2stop bit its working fine for none parity. i think for UART-0 i used virtual USB port that's why am not getting correct result. i put MAX232 for UART-1 and tried its ok. but still i have problem with 7E1.

when i type one by one character its displaying correctly but i transfer some 1kb file through hyperterminal or tereterm its outing junk value why.? and also am using "UART_DRV_InstallRxCallback" interrupt function to receive UART data. is any problem..?

regards,

sudhakar p

Re: how to set EVEN-7BIT-1 STOP BIT SETTING FOR FRDMK64

sudhakarp — Thu, 08 Oct 2015 05:48:02 GMT

hi,

thank you. i got it.everything i tried with UART-0 virtual USB port that's why am not getting correct result.

thank you very much.

regards,

sudhakar p