1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
|
;;
;; spreadspace pic utils
;;
;;
;; Copyright (C) 2011-2013 Christian Pointner <equinox@spreadspace.org>
;;
;; This file is part of spreadspace pic utils.
;;
;; spreadspace pic utils 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.
;;
;; spreadspace pic utils 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 spreadspace pic utils. If not, see <http://www.gnu.org/licenses/>.
;;
;; --- transmit byte and add it to csum
com_tx_byte
btfss PIR1,TXIF
goto com_tx_byte
movwf TXREG
xorwf csum,f
return
;; ---- wait for byte to be received
com_rx_byte
btfsc RCSTA,OERR
goto uart_rx_oe
btfss PIR1,RCIF
goto com_rx_byte
btfsc RCSTA,FERR
goto uart_rx_fe
movf RCREG,w
return
uart_rx_oe ; recover from overflow
bcf RCSTA,CREN
bsf RCSTA,CREN
goto com_rx_byte
uart_rx_fe ; recover from framing error
movf RCREG,w
goto com_rx_byte
;; ----- initialize com (this is called by bootmacro, it's not a subroutine - no return at the end)
com_init
;; bank 3
bsf STATUS,RP0
bsf STATUS,RP1
movlw b'00001000' ; TX non-inverted, 16bit Baudrate, no auto baud detect
movwf BAUDCTL
;; bank 1
bcf STATUS,RP1
movlw b'01110000' ; set internal OSC to 8MHz
movwf OSCCON
movlw b'00100100' ; Baudrate = High Speed, async mode, transmit enabled, 8bit
movwf TXSTA
movlw .34 ; Baudrate = 57600 (@ 8MHz) -> -0,79 % Error
;; movlw .51 ; Baudrate = 38400 (@ 8MHz) -> -0,002 % Error
;; movlw .103 ; Baudrate = 19200 (@ 8MHz) -> 0,16 % Error
movwf SPBRG
clrf SPBRGH
;; bank 0
bcf STATUS,RP0
movlw b'10010000' ; enable Serial Port, 8bit, enable continues receive, disable address detection
movwf RCSTA
|
