Однажды я наткнулся на пример от атмела и сделал свою реализацию. Работает уже год без проблем.
Сначала запуск железа:
Код
AT91F_PMC_EnablePeriphClock(AT91C_BASE_PMC,(1<<AT91C_ID_TWI));
*AT91C_TWI_CWGR=0x033C3C;
*AT91C_TWI_CWGR=0x033C3C;
Ну ессно и ножки включить, тут думаю каждый справится.
Далее собсна чтение:
Код
void ReadI2C(char *s,unsigned count,char dev,word iaddr)
{
unsigned i,stt,j;
if (count==0) return;
*AT91C_TWI_CWGR=0x030F0F;
*AT91C_TWI_CR=AT91C_TWI_MSEN;
stt=*AT91C_TWI_SR; while (!(stt&AT91C_TWI_TXCOMP)) {stt=*AT91C_TWI_SR;}
if (dev==0xD0) i=AT91C_TWI_IADRSZ_1_BYTE; else i=AT91C_TWI_IADRSZ_2_BYTE;
*AT91C_TWI_IADR=iaddr;
*AT91C_TWI_MMR=(dev<<15)|i|AT91C_TWI_MREAD;
if (count==1) {
*AT91C_TWI_CR=AT91C_TWI_START|AT91C_TWI_STOP;
stt=*AT91C_TWI_SR; while (!(stt&AT91C_TWI_TXCOMP)) {stt=*AT91C_TWI_SR;}
s[0]=*AT91C_TWI_RHR;
*AT91C_TWI_CR=AT91C_TWI_MSDIS;
return;
} else *AT91C_TWI_CR=AT91C_TWI_START;
s[0]=*AT91C_TWI_RHR;
for (i=0; i<count; i++) {
stt=*AT91C_TWI_SR; j=10000; while (!(stt&AT91C_TWI_RXRDY)&&--j) {stt=*AT91C_TWI_SR;}
if (!j) {error|=NOEEP; return;}
s[i]=*AT91C_TWI_RHR;
}
*AT91C_TWI_CR=AT91C_TWI_STOP;
stt=*AT91C_TWI_SR; while (!(stt&AT91C_TWI_TXCOMP)) {stt=*AT91C_TWI_SR;}
*AT91C_TWI_CR=AT91C_TWI_MSDIS;
}
{
unsigned i,stt,j;
if (count==0) return;
*AT91C_TWI_CWGR=0x030F0F;
*AT91C_TWI_CR=AT91C_TWI_MSEN;
stt=*AT91C_TWI_SR; while (!(stt&AT91C_TWI_TXCOMP)) {stt=*AT91C_TWI_SR;}
if (dev==0xD0) i=AT91C_TWI_IADRSZ_1_BYTE; else i=AT91C_TWI_IADRSZ_2_BYTE;
*AT91C_TWI_IADR=iaddr;
*AT91C_TWI_MMR=(dev<<15)|i|AT91C_TWI_MREAD;
if (count==1) {
*AT91C_TWI_CR=AT91C_TWI_START|AT91C_TWI_STOP;
stt=*AT91C_TWI_SR; while (!(stt&AT91C_TWI_TXCOMP)) {stt=*AT91C_TWI_SR;}
s[0]=*AT91C_TWI_RHR;
*AT91C_TWI_CR=AT91C_TWI_MSDIS;
return;
} else *AT91C_TWI_CR=AT91C_TWI_START;
s[0]=*AT91C_TWI_RHR;
for (i=0; i<count; i++) {
stt=*AT91C_TWI_SR; j=10000; while (!(stt&AT91C_TWI_RXRDY)&&--j) {stt=*AT91C_TWI_SR;}
if (!j) {error|=NOEEP; return;}
s[i]=*AT91C_TWI_RHR;
}
*AT91C_TWI_CR=AT91C_TWI_STOP;
stt=*AT91C_TWI_SR; while (!(stt&AT91C_TWI_TXCOMP)) {stt=*AT91C_TWI_SR;}
*AT91C_TWI_CR=AT91C_TWI_MSDIS;
}
И запись:
Код
void WriteI2C(char *s,unsigned count,char dev,word iaddr)
{
unsigned i,stt,j;
if (count==0) return;
switch (dev) {
case 0xEE: i=AT91C_TWI_IADRSZ_NO; *AT91C_TWI_CWGR=0x033C3C; break;
case 0xD0: i=AT91C_TWI_IADRSZ_1_BYTE; *AT91C_TWI_CWGR=0x030F0F; break;
case 0xA6:
case 0xA0: i=AT91C_TWI_IADRSZ_2_BYTE; *AT91C_TWI_CWGR=0x030F0F; break;
}
*AT91C_TWI_CR=AT91C_TWI_MSEN;
stt=*AT91C_TWI_SR; j=20000; while (!(stt&AT91C_TWI_TXCOMP)&&--j) {stt=*AT91C_TWI_SR;}
*AT91C_TWI_MMR=(dev<<15)|i;
*AT91C_TWI_IADR=iaddr;
if (count==1) {
*AT91C_TWI_CR=AT91C_TWI_START|AT91C_TWI_STOP;
*AT91C_TWI_THR=s[0];
stt=*AT91C_TWI_SR; j=20000; while (!(stt&AT91C_TWI_TXCOMP)&&--j) {stt=*AT91C_TWI_SR;}
*AT91C_TWI_CR=AT91C_TWI_MSDIS;
return;
} else *AT91C_TWI_CR=AT91C_TWI_START;
for (i=0; i<count; i++) {
*AT91C_TWI_THR=s[i];
stt=*AT91C_TWI_SR; j=20000; while (!(stt&AT91C_TWI_TXRDY)&&--j) {stt=*AT91C_TWI_SR;}
if (!j) {
error|=NOEEP;
return;}
}
*AT91C_TWI_CR=AT91C_TWI_STOP;
stt=*AT91C_TWI_SR; j=20000; while (!(stt&AT91C_TWI_TXCOMP)&&--j) {stt=*AT91C_TWI_SR;}
*AT91C_TWI_CR=AT91C_TWI_MSDIS;
}
{
unsigned i,stt,j;
if (count==0) return;
switch (dev) {
case 0xEE: i=AT91C_TWI_IADRSZ_NO; *AT91C_TWI_CWGR=0x033C3C; break;
case 0xD0: i=AT91C_TWI_IADRSZ_1_BYTE; *AT91C_TWI_CWGR=0x030F0F; break;
case 0xA6:
case 0xA0: i=AT91C_TWI_IADRSZ_2_BYTE; *AT91C_TWI_CWGR=0x030F0F; break;
}
*AT91C_TWI_CR=AT91C_TWI_MSEN;
stt=*AT91C_TWI_SR; j=20000; while (!(stt&AT91C_TWI_TXCOMP)&&--j) {stt=*AT91C_TWI_SR;}
*AT91C_TWI_MMR=(dev<<15)|i;
*AT91C_TWI_IADR=iaddr;
if (count==1) {
*AT91C_TWI_CR=AT91C_TWI_START|AT91C_TWI_STOP;
*AT91C_TWI_THR=s[0];
stt=*AT91C_TWI_SR; j=20000; while (!(stt&AT91C_TWI_TXCOMP)&&--j) {stt=*AT91C_TWI_SR;}
*AT91C_TWI_CR=AT91C_TWI_MSDIS;
return;
} else *AT91C_TWI_CR=AT91C_TWI_START;
for (i=0; i<count; i++) {
*AT91C_TWI_THR=s[i];
stt=*AT91C_TWI_SR; j=20000; while (!(stt&AT91C_TWI_TXRDY)&&--j) {stt=*AT91C_TWI_SR;}
if (!j) {
error|=NOEEP;
return;}
}
*AT91C_TWI_CR=AT91C_TWI_STOP;
stt=*AT91C_TWI_SR; j=20000; while (!(stt&AT91C_TWI_TXCOMP)&&--j) {stt=*AT91C_TWI_SR;}
*AT91C_TWI_CR=AT91C_TWI_MSDIS;
}
В примере записи происходит переключение скоростей под разную переферию. Используются часы, два епрома и пик. Все работает!
