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comparison duart28/eeprom_wr.c @ 31:530ec3792de8

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fc-duart28-conf: implement set command
author Mychaela Falconia <falcon@freecalypso.org>
date Sat, 09 Sep 2023 19:40:58 +0000
parents duart28/eeprom_rd.c@8de3891460db
children
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30:8de3891460db 31:530ec3792de8
1 /*
2 * This module implements the final step of modifying the EEPROM
3 * for the desired configuration.
4 */
5
6 #include <sys/types.h>
7 #include <stdio.h>
8 #include <stdlib.h>
9 #include <string.h>
10 #include <strings.h>
11 #include <usb.h>
12 #include "../libftmini/eeprom_func.h"
13
14 extern u_short eeprom[64];
15
16 static void
17 recompute_checksum()
18 {
19 u_short chksum = 0xAAAA;
20 unsigned n;
21
22 for (n = 0; n < 63; n++) {
23 chksum ^= eeprom[n];
24 chksum = (chksum << 1) | (chksum >> 15);
25 }
26 eeprom[63] = chksum;
27 }
28
29 void
30 update_eeprom(usbh, newconf)
31 usb_dev_handle *usbh;
32 {
33 switch (newconf) {
34 case 'C':
35 eeprom[2] = 0x7152;
36 break;
37 case 'S':
38 eeprom[2] = 0x6010;
39 break;
40 default:
41 fprintf(stderr, "BUG: wrong argument to update_eeprom()\n");
42 abort();
43 }
44 eeprom[31] = newconf;
45 recompute_checksum();
46 ftmini_write_eeprom_loc(usbh, 2, eeprom[2]);
47 ftmini_write_eeprom_loc(usbh, 31, eeprom[31]);
48 ftmini_write_eeprom_loc(usbh, 63, eeprom[63]);
49 }