From: Manu Abraham <abraham.manu@gmail.com>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
Sender: "piclist-bounces@mit.edu" <piclist-bounces@mit.edu>
Date: Thu, 30 Jul 2020 11:25:43 -0700
Subject: Re: [PIC] Simple GCC question
Thread-Topic: [PIC] Simple GCC question
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Hi Bob,

Sure, you are welcome, not a hassle.
Most code is similar a stone rolling through time,
Over time the sharp edges get nicely shaped.
Lot of public code is like that, it takes time and effort to evolve.

Best Regards,
Manu

On Thu, Jul 30, 2020 at 11:44 PM Bob Blick <bobblick@outlook.com> wrote:
>
> Hi Manu,
> I will give it a try. I guess I wasn't just too stupid not to be able to =
make it work without changes. Thank you very much.
> Bob
>
> ________________________________________
> From: piclist-bounces@mit.edu <piclist-bounces@mit.edu> on behalf of Manu=
 Abraham
> Sent: Thursday, July 30, 2020 10:49 AM
> To: Microcontroller discussion list - Public.
> Subject: Re: [PIC] Simple GCC question
>
> Hi Bob,
>
> Another look at the github code, I would do this:
>
> #define MODE ..
>
> #define EN_PIN    LL_GPIO_PIN_0
> #define EN_PORT GPIOB
> ..
> and more
>
> Lcd_HandleTypeDef lcd;  <-- make this global,
>
> int main(void)
> {
>
> .. do whatever ..
>
> lcd.mode =3D MODE;
>
> lcd.en_pin =3D EN_PIN;
> lcd.en_port =3D EN_PORT;
>
> lcd.rs_pin =3D rs_pin;
> lcd.rs_port =3D rs_port;
>
> lcd.data_pin =3D pin;
> lcd.data_port =3D port;
>
> Lcd_init(&lcd);
>
> .. do whatever ..
>
> }
>
> Lcd_init() happens to be public via lcd.h.
> So, you do not need to clobber the library,
> but just that you do not need to call Lcd_create() fn.
>
> Advantage, lower memory usage, lesser complexity. :-)
>
> Regards,
> Manu
>
> On Thu, Jul 30, 2020 at 11:08 PM Bob Blick  wrote:
> >
> > Hi Manu,
> >
> > Although the LCD will not normally be driven from interrupts, if there =
is a lockup I would like it to leave an error code on the display, which wo=
uld need to be done from an interrupt.
> >
> > I guess to make it global without errors I will need to hardcode the po=
rts and pins so I get rid of the arrays that are handed to Lcd_create()
> >
> > Thanks, Bob
> >
> > ________________________________________
> > From: piclist-bounces@mit.edu <piclist-bounces@mit.edu> on behalf of Ma=
nu Abraham
> > Sent: Thursday, July 30, 2020 9:55 AM
> > To: Microcontroller discussion list - Public.
> > Subject: Re: [PIC] Simple GCC question
> >
> > On Thu, Jul 30, 2020 at 9:57 PM Bob Blick wrote:
> > >
> > > I'm using a nice little HD44780 LCD library in an STM32 project, it w=
orks great but I'm stuck with a variable scope problem that I can only seem=
 to make worse because GCC is a bit stricter than I want it to be at this p=
oint. Sorry if the code example doesn't wordwrap properly.
> > >
> > > If, somewhere in main() I create an instance of the LCD like this:
> > >   Lcd_PortType ports[] =3D {LCD_D4_GPIO_Port, LCD_D5_GPIO_Port, LCD_D=
6_GPIO_Port, LCD_D7_GPIO_Port};
> > >   Lcd_PinType pins[] =3D {LCD_D4_Pin, LCD_D5_Pin, LCD_D6_Pin, LCD_D7_=
Pin};
> > >   Lcd_HandleTypeDef lcd =3D Lcd_create(ports, pins, LCD_RS_GPIO_Port,=
 LCD_RS_Pin, LCD_EN_GPIO_Port, LCD_EN_Pin, LCD_4_BIT_MODE);
> > >
> >
> > Why I dislike opaque datatypes...
> >
> > Instead of copying objects to Lcd_create(), a pointer could have been u=
sed,
> > storage could have been global, made static ..
> > the variables appear to be for configuration purposes ?
> >
> > One way to do is make the lcd object global.
> >
> > Another way is to pass a lcd object pointer to whatever function you
> > are calling,
> > unless you need to access the lcd object from interrupt context.
> > If you need access from interrupt context, the easier way is to have
> > global storage.
> >
> > --
> >
>
> --
> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist

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