| 1 |
2 |
olivier.gi |
#include "hardware.h"
|
| 2 |
|
|
|
| 3 |
|
|
;variables
|
| 4 |
|
|
.data
|
| 5 |
|
|
.comm rxdata,1,1 ;char var
|
| 6 |
|
|
.comm rxshift,1,1 ;char var
|
| 7 |
|
|
.comm rxbit,2,2 ;short var, aligned
|
| 8 |
|
|
|
| 9 |
|
|
.text
|
| 10 |
|
|
|
| 11 |
|
|
interrupt(TIMERA0_VECTOR) ;register interrupt vector
|
| 12 |
|
|
;interrupt handler to receive as Timer_A UART
|
| 13 |
|
|
.global ccr0 ;place a label afterwards so
|
| 14 |
|
|
ccr0: ;that it is used in the listing
|
| 15 |
|
|
add rxbit, r0
|
| 16 |
|
|
jmp .Lrxstart ;start bit
|
| 17 |
|
|
jmp .Lrxdatabit ;D0
|
| 18 |
|
|
jmp .Lrxdatabit ;D1
|
| 19 |
|
|
jmp .Lrxdatabit ;D2
|
| 20 |
|
|
jmp .Lrxdatabit ;D3
|
| 21 |
|
|
jmp .Lrxdatabit ;D4
|
| 22 |
|
|
jmp .Lrxdatabit ;D5
|
| 23 |
|
|
jmp .Lrxdatabit ;D6
|
| 24 |
|
|
; jmp .Lrxlastbit ;D7 that one is following anyway
|
| 25 |
|
|
|
| 26 |
|
|
.Lrxlastbit: ;last bit, handle byte
|
| 27 |
|
|
bit #SCCI, &CCTL0 ;read last bit
|
| 28 |
|
|
rrc.b rxshift ;and save it
|
| 29 |
|
|
clr rxbit ;reset state
|
| 30 |
|
|
mov #CCIE|CAP|CM_2|CCIS_1|SCS, &CCTL0 ;restore capture mode
|
| 31 |
|
|
mov.b rxshift, rxdata ;copy received data
|
| 32 |
|
|
bic #CPUOFF|OSCOFF|SCG0|SCG1, 0(r1) ;exit all lowpower modes
|
| 33 |
|
|
;here you might do other things too, like setting a flag
|
| 34 |
|
|
;that the wakeup comes from the Timer_A UART. however
|
| 35 |
|
|
;it should not take longer than one bit time, otherwise
|
| 36 |
|
|
;charcetrs will be lost.
|
| 37 |
|
|
reti
|
| 38 |
|
|
|
| 39 |
|
|
.Lrxstart: ;startbit, init
|
| 40 |
|
|
clr rxshift ;clear input buffer
|
| 41 |
|
|
add #(BAUD/2), &CCR0 ;startbit + 1.5 bits -> first bit
|
| 42 |
|
|
mov #CCIE|CCIS_1|SCS, &CCTL0;set compare mode, sample bits
|
| 43 |
|
|
jmp .Lrxex ;set state,...
|
| 44 |
|
|
|
| 45 |
|
|
.Lrxdatabit: ;save databit
|
| 46 |
|
|
bit #SCCI, &CCTL0 ;measure databit
|
| 47 |
|
|
rrc.b rxshift ;rotate in databit
|
| 48 |
|
|
|
| 49 |
|
|
.Lrxex: add #BAUD, &CCR0 ;one bit delay
|
| 50 |
|
|
incd rxbit ;setup next state
|
| 51 |
|
|
reti
|
| 52 |
|
|
|
| 53 |
|
|
; void serPutc(char)
|
| 54 |
|
|
;use an other Capture/Compare than for receiving (full duplex).
|
| 55 |
|
|
;this one is without interrupts and OUTMOD, because only
|
| 56 |
|
|
;this way P1.1 can be used. P1.1 is prefered because the
|
| 57 |
|
|
;BSL is on that pin too.
|
| 58 |
|
|
.global putchar
|
| 59 |
|
|
.type putchar, @function
|
| 60 |
|
|
putchar: ;send a byte
|
| 61 |
|
|
mov #0, &CCTL1 ;select compare mode
|
| 62 |
|
|
mov #10, r13 ;ten bits: Start, 8 Data, Stop
|
| 63 |
|
|
rla r15 ;shift in start bit (0)
|
| 64 |
|
|
bis #0x0200, r15 ;set tenth bit (1), thats the stop bit
|
| 65 |
|
|
mov &TAR, &CCR1 ;set up start time
|
| 66 |
|
|
.Lt1lp: add #BAUD, &CCR1 ;set up for one bit
|
| 67 |
|
|
rrc r15 ;shift data trough carry
|
| 68 |
|
|
jc .Lt1 ;test carry bit
|
| 69 |
|
|
.Lt0: bic.b #TX, &P1OUT ;generate pulse
|
| 70 |
|
|
jmp .Ltc ;
|
| 71 |
|
|
.Lt1: bis.b #TX, &P1OUT ;just use the same amount of time as for a zero
|
| 72 |
|
|
jmp .Ltc ;
|
| 73 |
|
|
.Ltc: bit #CCIFG, &CCTL1 ;wait for compare
|
| 74 |
|
|
jz .Ltc ;loop until the bit is set
|
| 75 |
|
|
bic #CCIFG, &CCTL1 ;clear for next loop
|
| 76 |
|
|
dec r13 ;decrement bit counter
|
| 77 |
|
|
jnz .Lt1lp ;loop until all bits are transmitted
|
| 78 |
|
|
ret
|
