157 rivejä
3.9 KiB
ArmAsm
157 rivejä
3.9 KiB
ArmAsm
|
;---------------------------------------------------------------------------;
|
||
|
|
; Software implemented UART module ;
|
||
|
|
; (C)ChaN, 2005 (http://elm-chan.org/) ;
|
||
|
|
;---------------------------------------------------------------------------;
|
||
|
|
; Bit rate settings:
|
||
|
|
;
|
||
|
|
; 1MHz 2MHz 4MHz 6MHz 8MHz 10MHz 12MHz 16MHz 20MHz
|
||
|
|
; 2.4kbps 138 - - - - - - - -
|
||
|
|
; 4.8kbps 68 138 - - - - - - -
|
||
|
|
; 9.6kbps 33 68 138 208 - - - - -
|
||
|
|
; 19.2kbps - 33 68 102 138 173 208 - -
|
||
|
|
; 38.4kbps - - 33 50 68 85 102 138 172
|
||
|
|
; 57.6kbps - - 21 33 44 56 68 91 114
|
||
|
|
; 115.2kbps - - - - 21 27 33 44 56
|
||
|
|
|
||
|
|
.nolist
|
||
|
|
#include <avr/io.h>
|
||
|
|
.list
|
||
|
|
|
||
|
|
#define BPS 102 /* Bit delay. (see above table) */
|
||
|
|
#define BIDIR 0 /* 0:Separated Tx/Rx, 1:Shared Tx/Rx */
|
||
|
|
|
||
|
|
#define OUT_1 sbi _SFR_IO_ADDR(SUART_OUT_PORT), SUART_OUT_BIT /* Output 1 */
|
||
|
|
#define OUT_0 cbi _SFR_IO_ADDR(SUART_OUT_PORT), SUART_OUT_BIT /* Output 0 */
|
||
|
|
#define SKIP_IN_1 sbis _SFR_IO_ADDR(SUART_IN_PIN), SUART_IN_BIT /* Skip if 1 */
|
||
|
|
#define SKIP_IN_0 sbic _SFR_IO_ADDR(SUART_IN_PIN), SUART_IN_BIT /* Skip if 0 */
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
#ifdef SPM_PAGESIZE
|
||
|
|
.macro _LPMI reg
|
||
|
|
lpm \reg, Z+
|
||
|
|
.endm
|
||
|
|
.macro _MOVW dh,dl, sh,sl
|
||
|
|
movw \dl, \sl
|
||
|
|
.endm
|
||
|
|
#else
|
||
|
|
.macro _LPMI reg
|
||
|
|
lpm
|
||
|
|
mov \reg, r0
|
||
|
|
adiw ZL, 1
|
||
|
|
.endm
|
||
|
|
.macro _MOVW dh,dl, sh,sl
|
||
|
|
mov \dl, \sl
|
||
|
|
mov \dh, \sh
|
||
|
|
.endm
|
||
|
|
#endif
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
;---------------------------------------------------------------------------;
|
||
|
|
; Transmit a byte in serial format of N81
|
||
|
|
;
|
||
|
|
;Prototype: void xmit (uint8_t data);
|
||
|
|
;Size: 16 words
|
||
|
|
|
||
|
|
.global xmit
|
||
|
|
.func xmit
|
||
|
|
xmit:
|
||
|
|
#if BIDIR
|
||
|
|
ldi r23, BPS-1 ;Pre-idle time for bidirectional data line
|
||
|
|
5: dec r23 ;
|
||
|
|
brne 5b ;/
|
||
|
|
#endif
|
||
|
|
in r0, _SFR_IO_ADDR(SREG) ;Save flags
|
||
|
|
|
||
|
|
com r24 ;C = start bit
|
||
|
|
ldi r25, 10 ;Bit counter
|
||
|
|
cli ;Start critical section
|
||
|
|
|
||
|
|
1: ldi r23, BPS-1 ;----- Bit transferring loop
|
||
|
|
2: dec r23 ;Wait for a bit time
|
||
|
|
brne 2b ;/
|
||
|
|
brcs 3f ;MISO = bit to be sent
|
||
|
|
OUT_1 ;
|
||
|
|
3: brcc 4f ;
|
||
|
|
OUT_0 ;/
|
||
|
|
4: lsr r24 ;Get next bit into C
|
||
|
|
dec r25 ;All bits sent?
|
||
|
|
brne 1b ; no, coutinue
|
||
|
|
|
||
|
|
out _SFR_IO_ADDR(SREG), r0 ;End of critical section
|
||
|
|
ret
|
||
|
|
.endfunc
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
;---------------------------------------------------------------------------;
|
||
|
|
; Receive a byte
|
||
|
|
;
|
||
|
|
;Prototype: uint8_t rcvr (void);
|
||
|
|
;Size: 19 words
|
||
|
|
|
||
|
|
.global rcvr
|
||
|
|
.func rcvr
|
||
|
|
rcvr:
|
||
|
|
in r0, _SFR_IO_ADDR(SREG) ;Save flags
|
||
|
|
|
||
|
|
ldi r24, 0x80 ;Receiving shift reg
|
||
|
|
cli ;Start critical section
|
||
|
|
|
||
|
|
1: SKIP_IN_1 ;Wait for idle
|
||
|
|
rjmp 1b
|
||
|
|
2: SKIP_IN_0 ;Wait for start bit
|
||
|
|
rjmp 2b
|
||
|
|
ldi r25, BPS/2 ;Wait for half bit time
|
||
|
|
3: dec r25
|
||
|
|
brne 3b
|
||
|
|
|
||
|
|
4: ldi r25, BPS ;----- Bit receiving loop
|
||
|
|
5: dec r25 ;Wait for a bit time
|
||
|
|
brne 5b ;/
|
||
|
|
lsr r24 ;Next bit
|
||
|
|
SKIP_IN_0 ;Get a data bit into r24.7
|
||
|
|
ori r24, 0x80
|
||
|
|
brcc 4b ;All bits received? no, continue
|
||
|
|
|
||
|
|
out _SFR_IO_ADDR(SREG), r0 ;End of critical section
|
||
|
|
ret
|
||
|
|
.endfunc
|
||
|
|
|
||
|
|
|
||
|
|
; Not wait for start bit. This should be called after detecting start bit.
|
||
|
|
.global recv
|
||
|
|
.func recv
|
||
|
|
recv:
|
||
|
|
in r0, _SFR_IO_ADDR(SREG) ;Save flags
|
||
|
|
|
||
|
|
ldi r24, 0x80 ;Receiving shift reg
|
||
|
|
cli ;Start critical section
|
||
|
|
|
||
|
|
;1: SKIP_IN_1 ;Wait for idle
|
||
|
|
; rjmp 1b
|
||
|
|
;2: SKIP_IN_0 ;Wait for start bit
|
||
|
|
; rjmp 2b
|
||
|
|
ldi r25, BPS/2 ;Wait for half bit time
|
||
|
|
3: dec r25
|
||
|
|
brne 3b
|
||
|
|
|
||
|
|
4: ldi r25, BPS ;----- Bit receiving loop
|
||
|
|
5: dec r25 ;Wait for a bit time
|
||
|
|
brne 5b ;/
|
||
|
|
lsr r24 ;Next bit
|
||
|
|
SKIP_IN_0 ;Get a data bit into r24.7
|
||
|
|
ori r24, 0x80
|
||
|
|
brcc 4b ;All bits received? no, continue
|
||
|
|
|
||
|
|
ldi r25, BPS/2 ;Wait for half bit time
|
||
|
|
6: dec r25
|
||
|
|
brne 6b
|
||
|
|
7: SKIP_IN_1 ;Wait for stop bit
|
||
|
|
rjmp 7b
|
||
|
|
|
||
|
|
out _SFR_IO_ADDR(SREG), r0 ;End of critical section
|
||
|
|
ret
|
||
|
|
.endfunc
|