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Some progress on i2c control.

master
Gavan Fantom 13 years ago
parent
85d33abdd9
commit
52e1c59a2e
5 changed files with 223 additions and 15 deletions
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  1. 14
      Makefile
  2. 104
      i2c.c
  3. 11
      i2c.h
  4. 106
      main.c
  5. 3
      types.h

14
Makefile
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@ -2,15 +2,16 @@
NAME=quad
OBJS=crt0.o main.o
SSRCS=crt0.s
CSRCS=main.c i2c.c
CFLAGS=-march=armv4t -msoft-float
CFLAGS=-march=armv4t -msoft-float -O1
LDSCRIPT=lpc2103_flash.ld
CC=arm-elf-gcc
OBJCOPY=arm-elf-objcopy
CLEANOBJS=$(OBJS) $(NAME).hex $(NAME).elf $(NAME).bin $(NAME).map
CLEANOBJS=$(OBJS) $(NAME).hex $(NAME).elf $(NAME).bin $(NAME).map .depend
all: $(NAME).bin
@ -18,6 +19,9 @@ all: $(NAME).bin
# In theory, nothing below here needs touching for as long as all of the
# sources are in a single directory.
COBJS=$(CSRCS:.c=.o)
SOBJS=$(SSRCS:.s=.o)
OBJS=$(SOBJS) $(COBJS)
.SUFFIXES: .elf .hex .bin
@ -36,3 +40,7 @@ run: $(NAME).hex
clean:
rm -rf $(CLEANOBJS)
depend:
$(CC) -MM $(CFLAGS) -nostdlib -nostartfiles $(CSRCS) >.depend
.sinclude ".depend"

104
i2c.c
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@ -0,0 +1,104 @@
#include "i2c.h"
#define I2CBASE 0xE001C000
#define I2CONSET 0x00
#define I2STAT 0x04
#define I2DAT 0x08
#define I2ADR 0x0c
#define I2SCLH 0x10
#define I2SCLL 0x14
#define I2CONCLR 0x18
#define IREG(x) (((volatile unsigned char *)I2CBASE)[x])
#define IWREG(x) (((volatile unsigned int *)I2CBASE)[(x)/sizeof(unsigned int)])
#define AAFLAG (1<<2)
#define SIFLAG (1<<3)
#define STOFLAG (1<<4)
#define STAFLAG (1<<5)
#define SI (IREG(I2CONSET) & SIFLAG)
void init_i2c(void)
{
IREG(I2CONSET) = 0x40; /* Enable I2C ready for Master Tx */
/* Set up for just under 400kHz */
#if 0
IWREG(I2SCLL) = (25 * 100);
IWREG(I2SCLH) = (12 * 100);
#else
IWREG(I2SCLL) = 1475; /* ~5kHz */
IWREG(I2SCLH) = 1475;
#endif
}
int i2cstat;
int i2c_wait(void)
{
int stat;
while (!SI);
stat = IREG(I2STAT);
i2cstat = stat;
return stat;
}
void i2c_go(void)
{
IREG(I2CONCLR) = SIFLAG;
}
int i2c_conreg(void)
{
return IREG(I2CONSET);
}
int i2c_statreg(void)
{
return IREG(I2STAT);
}
bool i2c_send_start(void)
{
IREG(I2CONCLR) = STOFLAG | STAFLAG;
IREG(I2CONSET) = STAFLAG;
/* i2c_go(); */
switch (i2c_wait()) {
case 0x08:
case 0x10:
/* IREG(I2CONCLR) = STAFLAG; */
return TRUE;
default:
/* IREG(I2CONCLR) = STAFLAG; */
return FALSE;
}
}
bool i2c_send_address(int addr, bool write)
{
return i2c_send_data((addr<<1) + (write?0:1));
}
bool i2c_send_data(int data)
{
IREG(I2DAT) = data;
IREG(I2CONCLR) = STAFLAG | SIFLAG;
switch (i2c_wait()) {
case 0x18:
case 0x28:
return TRUE;
default:
return FALSE;
}
}
void i2c_send_stop(void)
{
IREG(I2CONCLR) = STAFLAG | AAFLAG;
IREG(I2CONSET) = STOFLAG;
i2c_go();
/* Don't think we need to wait here. Could be wrong. */
}

11
i2c.h
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@ -0,0 +1,11 @@
#include "types.h"
void init_i2c(void);
extern int i2cstat;
int i2c_wait(void);
void i2c_go(void);
int i2c_conreg(void);
int i2c_statreg(void);
bool i2c_send_start(void);
bool i2c_send_address(int addr, bool write);
bool i2c_send_data(int data);
void i2c_send_stop(void);

106
main.c
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@ -1,4 +1,6 @@
#include "i2c.h"
#define UARTBASE 0xE000C000
#define RBR 0x00
@ -16,29 +18,47 @@
#define FDR 0x28
#define TER 0x30
#define REG(x) (((volatile unsigned char *)UARTBASE)[x])
#define UREG(x) (((volatile unsigned char *)UARTBASE)[x])
#define U0THRE ((UREG(LSR) & (1<<5))) /* UART0 transmitter holding register is empty */
#define U0DR ((UREG(LSR) & (1<<0))) /* UART0 data ready */
#define I2CBASE 0xE001C000
#define I2CONSET 0x00
#define I2STAT 0x04
#define I2DAT 0x08
#define I2ADR 0x0c
#define I2SCLH 0x10
#define I2SCLL 0x14
#define I2CONCLR 0x18
#define IREG(x) (((volatile unsigned char *)I2CBASE)[x])
#define U0THRE ((REG(LSR) & (1<<5))) /* UART0 transmitter holding register is empty */
#define U0DR ((REG(LSR) & (1<<0))) /* UART0 data ready */
#define PINSEL0 (*((volatile unsigned char *) 0xE002C000))
void init_uart(void)
{
REG(FDR) = 0x10; /* DivAddVal = 0, MulVal = 1 */
UREG(FDR) = 0x10; /* DivAddVal = 0, MulVal = 1 */
REG(LCR) = 0x80;
REG(DLM) = 0x00;
REG(DLL) = 0x08; /* 14745600 / (16*115200) */
REG(LCR) = 0x13;
REG(FCR) = 0x07;
UREG(LCR) = 0x80;
UREG(DLM) = 0x00;
UREG(DLL) = 0x08; /* 14745600 / (16*115200) */
UREG(LCR) = 0x13;
UREG(FCR) = 0x07;
}
PINSEL0 = 0x00000005; /* P0.0 and P0.1 assigned to UART */
void init_pins(void)
{
PINSEL0 = 0x00000055; /* P0.0 and P0.1 assigned to UART */
/* P0.2 and P0.3 assigned to I2C */
}
void putch(char c) {
while (!U0THRE);
REG(THR) = c;
UREG(THR) = c;
}
void putstr(char *s) {
@ -59,9 +79,26 @@ void putint(unsigned int n) {
putstr(s+i);
}
void puthex(unsigned int n) {
char s[9];
int i;
i = 8;
s[i] = '\0';
do {
int x = n % 16;
if (x > 9)
x += 'A' - '0' - 10;
s[--i] = x + '0';
} while ((n /= 16) > 0);
putstr(s+i);
}
char getch(void) {
while (!U0DR);
return REG(RBR);
return UREG(RBR);
}
void reply(char *str)
@ -74,6 +111,8 @@ unsigned int count = 0;
int main(void) {
init_uart();
init_i2c();
init_pins();
putstr("Your entire life has been a mathematical error... a mathematical error I'm about to correct!\r\n");
while (1) {
@ -101,6 +140,49 @@ int main(void) {
case '?':
reply("Help is not available. Try a psychiatrist.");
break;
case 'R':
putstr("I2C register is: ");
puthex(i2c_conreg());
reply(".");
break;
case 'T':
putstr("I2C status was: ");
puthex(i2cstat);
putstr(" I2C status is: ");
puthex(i2c_statreg());
reply(".");
break;
case 'S':
putstr("Sending START... ");
if (i2c_send_start())
reply("OK");
else
reply("FAIL");
break;
case 'D':
putstr("Sending address... ");
if (i2c_send_address(0x53, TRUE))
reply("OK");
else
reply("FAIL");
break;
case 'B':
putstr("Sending bytes... ");
if (i2c_send_data(0xfe))
reply("OK");
else
reply("FAIL");
if (i2c_send_data(0x04))
reply("OK");
else
reply("FAIL");
break;
case 'O':
putstr("Sending STOP... ");
i2c_send_stop();
reply("sent");
break;
default:
reply("Unrecognised command.");
break;

3
types.h
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@ -0,0 +1,3 @@
typedef int bool;
#define TRUE 1
#define FALSE 0
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