Hello! Please, help me.
I use Eclipse + gcc + JTAG to programm AT91SAM7S64. I get universal code
to use with my LCD with controller (hereunder). The lines like LCD.E=0;
Delay(>20ms); should be modified correctly and structure LCD with pins
sould be declared. I would like to understand how to use constructions
like LCD.E=1. Currently I use mask in my code:
In board.h define pins of LCD ----------------
#define DB0 (1<<0) // DB0 pin of LCD
#define DB1 (1<<1) // DB1 pin of LCD
#define DB2 (1<<2) // DB2 pin of LCD
#define DB3 (1<<3) // DB3 pin of LCD
#define A0 (1<<4) // A0 pin of LCD
#define RDRW (1<<5) // Read/Write pin
#define E (1<<6) // E pin
#define DB7 (1<<7) // DB7
#define DB6 (1<<9) // DB6
#define DB5 (1<<10) // DB5
#define DB4 (1<<11) // DB4
#define MY_MASK (DB0|DB1|DB2|DB3|A0|RDRW|E|DB7|DB6|DB5|DB4)
--------------------------------------------
And in main.c I write to init LCD something like this:
/// Swith off all pins
pPIO->PIO_CODR = E; //OFF
pPIO->PIO_CODR = A0; //OFF
pPIO->PIO_CODR = RDRW; //OFF
pPIO->PIO_CODR = DB7; //OFF
pPIO->PIO_CODR = DB6; //OFF
pPIO->PIO_CODR = DB5; //OFF
pPIO->PIO_CODR = DB4; //OFF
pPIO->PIO_CODR = DB3; //OFF
pPIO->PIO_CODR = DB2; //OFF
pPIO->PIO_CODR = DB1; //OFF
pPIO->PIO_CODR = DB0; //OFF
// Step 1
wait(150);
pPIO->PIO_CODR = E; //OFF
wait(10);
pPIO->PIO_CODR = A0; //OFF
pPIO->PIO_SODR = DB5; //ON
pPIO->PIO_SODR = DB4; //ON
pPIO->PIO_SODR = E; //ON
// Step 3
wait(100);
pPIO->PIO_CODR = E; //OFF
wait(10);
pPIO->PIO_SODR = DB5; //ON
......
----------------------------------------------
In PIC C I can make something like this
LCD={E==portA.1,A0==PortA.5, RDRW==portA.4, DB7==portA.7, ....,
DB0==portB4};
And use LCD.E=0; or LCD.1=0; in code. Or write LCD = 0x0040; without
pPIO->PIO_CODR etc.
How can I bild some structure with links to set of pins in gcc? And how
can I work with it without commands like "pPIO->" using just "=" and
HEX, DEC or binary numbers? I would like to use downloaded code
hereunder:
UNIVERSAL CODE FOR LCD: --------------------
#define MT10S1 //Type of LCD
#define Len1 8 //Symbols in first line of LCD
#define Len2 2 //Symbols in second line of LCD
#define Len3 0 //In 3th
#define Len4 0 //In 4th
const char Text1[Len1]={ 'M','E','L','T',' ','1','0','S' };
const char Text2[Len2]={ '1',24 };
void main(void) {
int i;
LCDinit();
WriteCmd(0x80); //Set cursor in start of first line
#if Len1>0
for(i=0;i<Len1;i++) { WriteData(Text1[i]); }
#endif
#if Len3>0
for(i=0;i<Len3;i++) { WriteData(Text3[i]); }
#endif
WriteCmd(0x80+0x40); //Set in start of second line
#if Len2>0
for(i=0;i<Len2;i++) { WriteData(Text2[i]); }
#endif
#if Len4>0
for(i=0;i<Len4;i++) { WriteData(Text4[i]); }
#endif
}
void LCDinit(void) {
LCD.E=0; Delay(>20ms);
//Set data pins for exit if needed
LCD.RW=0; LCD.A0=0; LCD.D=0x30; //8 bit interface setup
Delay(>40ns); //Pause
LCD.E=1; Delay(>230ns); //Время предустановки данных попало сюда
(tDSW)
LCD.E=0; Delay(>40us); //Пауза между командами
LCD.E=1; Delay(>230ns); //Минимально допустимая длительность сигнала
E=1
LCD.E=0; Delay(>40us); //Пауза между командами
LCD.E=1; Delay(>230ns);
LCD.E=0; Delay(>270ns); //Минимально допустимый интервал между
сигналами E=1
//Здесь индикатор входит в рабочий режим с установленным типом
интерфейса и можно подавать команды как обычно
WriteCmd(0x3A); //Настройка правильного режима ЖКИ
WriteCmd(0x0C); //Включение индикатора, курсор выключен
WriteCmd(0x01); //LCD CLEAR
WriteCmd(0x06); //Установка режима ввода данных: сдвигать курсор
вправо
}
void WriteCmd(byte b) { WriteByte(b,0); }
void WriteData(byte b) { WriteByte(b,1); }
void WriteByte(byte b, bit cd) {
//Сначала проверим готовность индикатора
//При необходимости настроить здесь шину данных на ввод
LCD.RW=1; LCD.A0=0; //Чтение флага занятости
Delay(>40ns); //Это время предустановки адреса (tAS)
LCD.E=1; Delay(>230ns); //Это минимально допустимая длительность
сигнала E=1 (информация на шину данных индикатором будет выдана раньше,
не более чем через 120нс)
while(LCD.D.7==1); //Ждать сброса флага занятости
LCD.E=0; Delay(>270ns); //Минимально допустимый интервал между
сигналами E=1
//При необходимости настроить здесь шину данных на вывод
LCD.RW=0; LCD.A0=cd; LCD.D=b;
Delay(>40ns); //Это время предустановки адреса (tAS)
LCD.E=1; Delay(>230ns); //Время предустановки данных попало сюда
(tDSW)
LCD.E=0; Delay(>270ns); //Минимально допустимый интервал между
сигналами E=1
}
Dima Bulkin wrote: > I would like to understand how to use constructions > like LCD.E=1. Theoretically this is possible with bitfields which are mapped to the hardware-address of a register. But AFAIK gcc does not create "correct" 32-bit read/writes and may "optimize" to 8-bit which will throw an exception. This issue has been mentioned in this forum before (several month ago). There is a patch for this in the gcc bugzilla but it did not work for me. I have asked the author of the patch and he admitted that it is not correct. Have to add: I tested sometime in May or June so maybe this is already fixed. Also for GPIO the Target has to allow some kind of direct write to a register (not just CLR/SET "Flip-Flop"-access). Most newer ARM-controllers provide this. Better try to modify the downloaded code and use some macros or inline-functions which can be easily modified for different targets (hardware abstraction layer i.e. LCD_RW_LOW, LCD_RW_HIGH etc.) so you do not need any specific compiler feature or non-standard-extension (i.e. IAR ICCARM has an extension for this kind of access). The "hal" will save you a lot of time later when you reuse your components for another compiler/target. Martin Thomas
Thank you for advice, Martin. I will choose that way.
Hi there Martin Thomas wrote: > Theoretically this is possible with bitfields which are mapped to the > hardware-address of a register. But AFAIK gcc does not create "correct" > 32-bit read/writes and may "optimize" to 8-bit which will throw an > exception. This issue has been mentioned in this forum before (several > month ago). There is a patch for this in the gcc bugzilla but it did not > work for me. I've run into this exact same problem, trying to configure my peripherals via structures, containing bitfields. I'm running a ST STR912, under GCC 4.3.1, Newlib, OpenOCD and Eclipse, options: --target=arm-elf --with-cpu=arm966e-s I've seen in the GCC compiler options page (http://gcc.gnu.org/onlinedocs/gcc-4.3.0/gcc/ARM-Options.html#ARM-Options and http://gcc.gnu.org/onlinedocs/gcc-4.3.0/gcc/MCore-Options.html#MCore-Options) that the MCore architecture has an option: -mwide-bitfields, that forces the access to the bitfield address as an int. I think a similar options should solve the problem for ARMs. ARM has a similar compiler option, but I think that this applies to the structure as a whole, and not individual members of the structure: " -mstructure-size-boundary=n The size of all structures and unions will be rounded up to a multiple of the number of bits set by this option... " Could you perhaps provide me with the bugzilla entry, so that I could follow it up with the GCC authors? BTW - could you see with newer GCCs if it was resolved? Regards, Frikkie Thirion
Frikkie Thirion wrote: > Could you perhaps provide me with the bugzilla entry, so that I could > follow it up with the GCC authors? Please see the old thread: http://en.mikrocontroller.net/topic/81611#new > BTW - could you see with newer GCCs if it was resolved? Sorry, I don't know. I will try again once I have gcc 4.3.1 installed.
Martin Thomas wrote: > Frikkie Thirion wrote: >> Could you perhaps provide me with the bugzilla entry, so that I could >> follow it up with the GCC authors? > Please see the old thread: http://en.mikrocontroller.net/topic/81611#new > >> BTW - could you see with newer GCCs if it was resolved? > Sorry, I don't know. I will try again once I have gcc 4.3.1 installed. Thank you for the reply. I've tested the bitfield accesses on the HiTex (www.hitex.com) instruction set simulator: HiTOP 5 (with GCC 4.1.1), which is quite good. I could see in the disassebled view in the debugger that the assembler used to implement my C code is using "ldrb" and "strb", which are byte accesses when I manipulate bitfield structures. If I access the memory location with a 32-bit pointer, I could see in the disassebled that "ldr" and "str" is used. Maybe I should rethink my register accesses to move away from bitfields all together - what a pitty...
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