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|
;;
;; mur.sat
;;
;; Somewhen in the year 2011, mur.at will have a nano satellite launched
;; into a low earth orbit (310 km above the surface of our planet). The
;; satellite itself is a TubeSat personal satellite kit, developed and
;; launched by interorbital systems. mur.sat is a joint venture of mur.at,
;; ESC im Labor and realraum.
;;
;; Please visit the project hompage at sat.mur.at for further information.
;;
;;
;; Copyright (C) 2011 Christian Pointner <equinox@mur.at>
;;
;; This file is part of mur.sat.
;;
;; mur.sat is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; any later version.
;;
;; mur.sat is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with mur.sat. If not, see <http://www.gnu.org/licenses/>.
;;
;; -------------------------------------
i2c_start
bsf STATUS,RP0
bcf TRISB,RTC_SDA
nop
bcf TRISB,RTC_SCL
bcf STATUS,RP0
return
;; ------------------
i2c_restart
bsf STATUS,RP0
bsf TRISB,RTC_SDA
nop
bsf TRISB,RTC_SCL
nop
nop
nop
bcf TRISB,RTC_SDA
nop
bcf TRISB,RTC_SCL
bcf STATUS,RP0
return
;; ------------------
i2c_stop
bsf STATUS,RP0
bsf TRISB,RTC_SCL
nop
bsf TRISB,RTC_SDA
bcf STATUS,RP0
return
;; ------------------
i2c_send_byte
movwf RTC_BYTE
movlw .8
movwf RTC_BIT_CNT
bsf STATUS,RP0
i2c_send_byte_next
btfss RTC_BYTE,7
bcf TRISB,RTC_SDA
btfsc RTC_BYTE,7
bsf TRISB,RTC_SDA
nop
bsf TRISB,RTC_SCL
nop
nop
bcf TRISB,RTC_SCL
rlf RTC_BYTE,f
decfsz RTC_BIT_CNT,f
goto i2c_send_byte_next
nop
nop
bsf TRISB,RTC_SDA
bsf TRISB,RTC_SCL
bcf STATUS,RP0
movf PORTB,w
bsf STATUS,RP0
bcf TRISB,RTC_SCL
bcf TRISB,RTC_SDA
bcf STATUS,RP0
andlw b'00010000'
movwf RTC_BYTE
swapf RTC_BYTE,f
return
;; ------------------
i2c_recv_byte
clrf RTC_BYTE
movlw .8
movwf RTC_BIT_CNT
bsf STATUS,RP0
bsf TRISB,RTC_SDA
i2c_recv_byte_loop
bsf TRISB,RTC_SCL
bcf STATUS,RP0
btfsc PORTB,RTC_SDA
bsf RTC_BYTE,0
bsf STATUS,RP0
bcf TRISB,RTC_SCL
decfsz RTC_BIT_CNT,f
goto i2c_recv_byte_next
bcf TRISB,RTC_SDA
bcf STATUS,RP0
return
i2c_recv_byte_next
bcf STATUS,C
rlf RTC_BYTE,f
goto i2c_recv_byte_loop
;; ------------------
i2c_ack
bsf STATUS,RP0
bcf TRISB,RTC_SDA
bsf TRISB,RTC_SCL
nop
nop
bcf TRISB,RTC_SCL
bcf STATUS,RP0
return
;; ------------------
i2c_nack
bsf STATUS,RP0
bsf TRISB,RTC_SDA
bsf TRISB,RTC_SCL
nop
nop
bcf TRISB,RTC_SCL
bcf TRISB,RTC_SDA
bcf STATUS,RP0
return
;; -------------------------------------
rtc_init
call i2c_start
movlw RTC_ADDR_W
call i2c_send_byte
btfsc RTC_BYTE,0
goto rtc_error_ack
movlw RTC_REG_STAT
call i2c_send_byte
btfsc RTC_BYTE,0
goto rtc_error_ack
call i2c_restart
movlw RTC_ADDR_R
call i2c_send_byte
btfsc RTC_BYTE,0
goto rtc_error_ack
call i2c_recv_byte
call i2c_nack
btfsc RTC_BYTE,7
goto rtc_init_after_clock_fail
call i2c_stop
return
rtc_init_after_clock_fail
call i2c_restart
movlw RTC_ADDR_W
call i2c_send_byte
btfsc RTC_BYTE,0
goto rtc_error_ack
movlw RTC_REG_SEC
call i2c_send_byte
btfsc RTC_BYTE,0
goto rtc_error_ack
movlw .16
movwf RTC_BYTE_CNT
rtc_init_clear
clrw
call i2c_send_byte
btfsc RTC_BYTE,0
goto rtc_error_ack
decfsz RTC_BYTE_CNT,f
goto rtc_init_clear
call i2c_stop
return
;; ---------------
rtc_get_time
call i2c_start
movlw RTC_ADDR_W
call i2c_send_byte
btfsc RTC_BYTE,0
goto rtc_error_ack
movlw RTC_REG_SEC
call i2c_send_byte
btfsc RTC_BYTE,0
goto rtc_error_ack
call i2c_restart
movlw RTC_ADDR_R
call i2c_send_byte
btfsc RTC_BYTE,0
goto rtc_error_ack
movlw .7
movwf RTC_BYTE_CNT
rtc_get_time_loop
call i2c_recv_byte
movf RTC_BYTE,w
movwf INDF
decfsz RTC_BYTE_CNT,f
goto rtc_get_time_next
call i2c_nack
call i2c_stop
return
rtc_get_time_next
incf FSR,f
call i2c_ack
goto rtc_get_time_loop
;; ---------------
rtc_error_ack
call i2c_stop
;; TODO: add error handling
return
;; -------------------------------------
|
