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Rework code for USB interface
author Daniel O'Connor <darius@dons.net.au>
date Sun, 19 Nov 2017 18:10:23 +1030
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-1:000000000000 0:1f3c12ba927d
1 INT16U cal_crc_half(INT8U far *pin, INT8U len)
2 {
3
4 INT16U crc;
5
6 INT8U da;
7 INT8U far *ptr;
8 INT8U bCRCHign;
9 INT8U bCRCLow;
10
11 INT16U crc_ta[16]=
12 {
13 0x0000,0x1021,0x2042,0x3063,0x4084,0x50a5,0x60c6,0x70e7,
14
15 0x8108,0x9129,0xa14a,0xb16b,0xc18c,0xd1ad,0xe1ce,0xf1ef
16 };
17 ptr=pin;
18 crc=0;
19
20 while(len--!=0)
21 {
22 da=((INT8U)(crc>>8))>>4;
23
24 crc<<=4;
25
26 crc^=crc_ta[da^(*ptr>>4)];
27
28 da=((INT8U)(crc>>8))>>4;
29
30 crc<<=4;
31
32 crc^=crc_ta[da^(*ptr&0x0f)];
33
34 ptr++;
35 }
36 bCRCLow = crc;
37
38 bCRCHign= (INT8U)(crc>>8);
39
40 if(bCRCLow==0x28||bCRCLow==0x0d||bCRCLow==0x0a)
41
42 {
43 bCRCLow++;
44 }
45 if(bCRCHign==0x28||bCRCHign==0x0d||bCRCHign==0x0a)
46
47 {
48 bCRCHign++;
49 }
50 crc = ((INT16U)bCRCHign)<<8;
51 crc += bCRCLow;
52 return(crc);
53 }