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3608c106 UH |
1 | /** |
2 | * Copyright (C) 2009 Ubixum, Inc. | |
3 | * | |
4 | * This library is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU Lesser General Public | |
6 | * License as published by the Free Software Foundation; either | |
7 | * version 2.1 of the License, or (at your option) any later version. | |
8 | * | |
9 | * This library is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
12 | * Lesser General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU Lesser General Public | |
040a6eae | 15 | * License along with this library; if not, see <http://www.gnu.org/licenses/>. |
3608c106 UH |
16 | **/ |
17 | ||
18 | ||
19 | #include <fx2regs.h> | |
20 | #include <fx2macros.h> | |
21 | #include <serial.h> | |
22 | ||
23 | ||
24 | /** | |
25 | * using the comp port implies that timer 2 will be used as | |
26 | * a baud rate generator. (Don't use timer 2) | |
27 | **/ | |
28 | void sio0_init( WORD baud_rate ) __critical { // baud_rate max should be 57600 since int=2 bytes | |
29 | ||
30 | WORD hl; // hl value for reload | |
31 | BYTE mult; // multiplier for clock speed | |
32 | DWORD tmp; // scratch for mult/divide | |
33 | ||
34 | // 0 = 12mhz, 1=24mhz, 2=48mhz | |
35 | mult = CPUFREQ == CLK_12M ? 1 : | |
36 | CPUFREQ == CLK_24M ? 2 : 4; // since only 3 clock speeds, fast switch instead of doing 2^clock speed pow(2,clkspd) | |
37 | ||
38 | // set the clock rate | |
39 | // use clock 2 | |
40 | RCLK=1;TCLK=1; | |
41 | ||
42 | // RCAP2H:L = 0xFFFF - CLKOUT / 32 x baud_rate | |
43 | ||
44 | // in order to round to nearest value.. | |
45 | // tmp * 2 // double | |
46 | // tmp / rate // do the divide | |
47 | // tmp + 1 // add one (which is like adding 1/2) | |
48 | // tmp / 2 // back to original rounded | |
49 | tmp = mult * 375000L * 2 ; | |
50 | tmp /= baud_rate; | |
51 | tmp += 1; | |
52 | tmp /= 2; | |
53 | ||
54 | hl = 0xFFFF - (WORD)tmp; | |
55 | ||
56 | RCAP2H= MSB(hl); | |
57 | // seems that the 24/48mhz calculations are always one less than suggested values | |
58 | // trm table 14-16 | |
59 | RCAP2L= LSB(hl) + (mult>0?1:0); | |
60 | TR2=1; // start the timer | |
61 | ||
62 | // set up the serial port | |
63 | SM0 = 0; SM1=1;// serial mode 1 (asyncronous) | |
64 | SM2 = 0 ; // has to do with receiving | |
65 | REN = 1 ; // to enable receiving | |
66 | PCON |= 0x80; // SET SMOD0, baud rate doubler | |
67 | TI = 1; // we send initial byte | |
68 | ||
69 | } | |
70 | ||
71 | char getchar() { | |
72 | char c; | |
73 | while (!RI) | |
74 | ; | |
75 | c=SBUF0; | |
76 | RI=0; | |
77 | return c; | |
78 | } | |
79 | ||
80 | void _transchar(char c) { | |
81 | while ( !TI ); // wait for TI=1 | |
82 | TI=0; | |
83 | SBUF0=c; | |
84 | } | |
85 | ||
86 | void putchar (char c) { | |
87 | if (c=='\n') _transchar('\r'); // transmit \r\n | |
88 | _transchar(c); | |
89 | if (c == '\r' ) _transchar('\n'); // transmit \r\n | |
90 | } | |
91 |