ref: f4122cfbc9ee6b99f69f1194ea38565fdfad36bb
dir: /sys/src/boot/bitsy/uart.c/
#include "u.h"
#include "lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "io.h"
enum
{
/* ctl[0] bits */
Parity= 1<<0,
Even= 1<<1,
Stop2= 1<<2,
Bits8= 1<<3,
SCE= 1<<4, /* synchronous clock enable */
RCE= 1<<5, /* rx on falling edge of clock */
TCE= 1<<6, /* tx on falling edge of clock */
/* ctl[3] bits */
Rena= 1<<0, /* receiver enable */
Tena= 1<<1, /* transmitter enable */
Break= 1<<2, /* force TXD3 low */
Rintena= 1<<3, /* enable receive interrupt */
Tintena= 1<<4, /* enable transmitter interrupt */
Loopback= 1<<5, /* loop back data */
/* data bits */
DEparity= 1<<8, /* parity error */
DEframe= 1<<9, /* framing error */
DEoverrun= 1<<10, /* overrun error */
/* status[0] bits */
Tint= 1<<0, /* transmit fifo half full interrupt */
Rint0= 1<<1, /* receiver fifo 1/3-2/3 full */
Rint1= 1<<2, /* receiver fifo not empty and receiver idle */
Breakstart= 1<<3,
Breakend= 1<<4,
Fifoerror= 1<<5, /* fifo error */
/* status[1] bits */
Tbusy= 1<<0, /* transmitting */
Rnotempty= 1<<1, /* receive fifo not empty */
Tnotfull= 1<<2, /* transmit fifo not full */
ParityError= 1<<3,
FrameError= 1<<4,
Overrun= 1<<5,
};
Uartregs *uart3regs = (Uartregs*)UART3REGS;
/*
* for iprint, just write it
*/
void
serialputs(char *str, int n)
{
Uartregs *ur;
ur = uart3regs;
while(n-- > 0){
/* wait for output ready */
while((ur->status[1] & Tnotfull) == 0)
;
ur->data = *str++;
}
while((ur->status[1] & Tbusy))
;
}