UART parity in driver usart_001.h incorrect

[vivienwong]

Hi,

    I am currently using the lpc_ip driver usart_001.h and realized that there is an error in the definition of the UART parity bits:    The driver sets it to:

typedef enum IP_UART_PARITY {

    UART_PARITY_NONE = 0,                                    /*!< No parity */

    UART_PARITY_ODD = (4 << 3),                                /*!< Odd parity */

    UART_PARITY_EVEN = (5 << 3),                            /*!< Even parity */

    UART_PARITY_SP_1 = (6 << 3),                            /*!< Forced "1" stick parity */

    UART_PARITY_SP_0 = (7 << 3)                                /*!< Forced "0" stick parity */

} IP_UART_PARITY_T;

However, based on the LPC18xx user manual, I believe this should be set to

typedef enum IP_UART_PARITY {

    UART_PARITY_NONE = 0,                                    /*!< No parity */

    UART_PARITY_ODD = (1 << 3),                                /*!< Odd parity */

    UART_PARITY_EVEN = (3 << 3),                            /*!< Even parity */

    UART_PARITY_SP_1 = (5 << 3),                            /*!< Forced "1" stick parity */

    UART_PARITY_SP_0 = (7 << 3)                                /*!< Forced "0" stick parity */

} IP_UART_PARITY_T;

  I have debug on my board and confirm that this could be an error on the driver.

[vivienwong]

Great! Thank you

[kerryzhou]

If this post answers your question, please click the Correct Answer button. Thank you!

[vivienwong]

Hi,

  Thank you for confirming that my change is correct.

I got this file from LPCOpen Platform:

LPCOpen Platform: C:/nxp/v1.03/lpcopen_v1.03/lpcopen/software/lpc_core/lpc_ip/usart_001.h Source Fil...

See line 406.

  I didn't write this myself but downloaded from NXP. I inherited this code from a colleague so I'm not exactly sure where he downloaded it but it's definitely not written by him. It was from NXP.

[kerryzhou]

Hi Vivien,

  Thank you for your more information, your lpcopen code is really the older version, it is v1.3, but now, we have v2.xx now, please refer to the newest lpcopen code:

LPCOpen Software for LPC18XX|NXP

  This problem has been fixed in the new version, just as I post it in the floor 2.

Wish it helps you!

Have a great day,
Jingjing

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[vivienwong]

Hi,

  I agree that your snapshots are correct. I didn't think these were wrong in the first place. The user manual and the #defines are correct. It is the enum definition that is incorrect.

However in that same usart_001.h file, the enum,definition is what i think is incorrect. You can find this lower in the file after the #defines.

typedef enum IP_UART_PARITY {

    UART_PARITY_NONE = 0,                                    /*!< No parity */

    UART_PARITY_ODD = (4 << 3),                                /*!< Odd parity */

    UART_PARITY_EVEN = (5 << 3),                            /*!< Even parity */

    UART_PARITY_SP_1 = (6 << 3),                            /*!< Forced "1" stick parity */

    UART_PARITY_SP_0 = (7 << 3)                                /*!< Forced "0" stick parity */

} IP_UART_PARITY_T;

I don't think this is correct and it should be:

typedef enum IP_UART_PARITY {

    UART_PARITY_NONE = 0,                                    /*!< No parity */

    UART_PARITY_ODD = (1 << 3),                                /*!< Odd parity */

    UART_PARITY_EVEN = (3 << 3),                            /*!< Even parity */

    UART_PARITY_SP_1 = (5 << 3),                            /*!< Forced "1" stick parity */

    UART_PARITY_SP_0 = (7 << 3)                                /*!< Forced "0" stick parity */

} IP_UART_PARITY_T;

[kerryzhou]

Hi Vivien,

      Did you write the usart_001.h by yourself?  I can't find this header file. Did you get this file from the official website?

     odd parity, even parity, forced'1' and forece'0' stick parity are all bit 5:4 in the LCR register, enable disable parity is bit 3..

  Take your post code as an example:

You think incorrect item:

typedef enum IP_UART_PARITY {

    UART_PARITY_NONE = 0,                                    /*!< No parity */

    UART_PARITY_ODD = (4 << 3),                                /*!< Odd parity */

    UART_PARITY_EVEN = (5 << 3),                            /*!< Even parity */

    UART_PARITY_SP_1 = (6 << 3),                            /*!< Forced "1" stick parity */

    UART_PARITY_SP_0 = (7 << 3)                                /*!< Forced "0" stick parity */

} IP_UART_PARITY_T;

UART_PARITY_NONE =0;    bit3 is 0x0, disable parity should be 0

UART_PARITY_ODD = 0x20; bit5,4 is 0X2, but odd parity should be 0x0;  bit3 should be 1, not correct.

UART_PARITY_EVEN=0X28;  bit5,4 is 0X2, but even parity should be 0x1; not correct.

UART_PARITY_SP_1=0X30;  bit5,4 is 0X3, but SP_1 parity should be 0x2;  bit3 should be 1, not correct.

UART_PARITY_SP_0=0X38; bit5,4 is 0X3, but SP_0 parity should be 0x3; correct.

You think correct item:

typedef enum IP_UART_PARITY {

    UART_PARITY_NONE = 0,                                    /*!< No parity */

    UART_PARITY_ODD = (1 << 3),                                /*!< Odd parity */

    UART_PARITY_EVEN = (3 << 3),                            /*!< Even parity */

    UART_PARITY_SP_1 = (5 << 3),                            /*!< Forced "1" stick parity */

    UART_PARITY_SP_0 = (7 << 3)                                /*!< Forced "0" stick parity */

} IP_UART_PARITY_T;

UART_PARITY_NONE =0;    bit3 is 0x0, disable parity should be 0; correct.

UART_PARITY_ODD = 0x08; bit5,4 is 0X0,  odd parity should be 0x0; correct.

UART_PARITY_EVEN=0X18;  bit5,4 is 0X1, even parity should be 0x1; correct.

UART_PARITY_SP_1=0X28;  bit5,4 is 0X2, SP_1 parity should be 0x2; correct.

UART_PARITY_SP_0=0X38;  bit5,4 is 0X3, SP_0 parity should be 0x3; correct.

so, after the analysis, your modified enum IP_UART_PARITY is correct.

Have a great day,
Jingjing

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[kerryzhou]

Hi Vivien,

  Please tell us where you get  usart_001.h?

  I have check the lpcopen for LPC1857 from this link:

LPCOpen Software for LPC18XX|NXP

  The partity is defined like this:

And from the datasheet, we can get that:

  So, the lpcopen driver uart parity definition is correct, you can refer to our lpcopen driver.

Wish it helps you!

If you still have question, please let me know!

Have a great day,
Jingjing

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