ref: 1b09060f468f530af2f4ef75441a40084e912e54
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)) ; }