Linx EVM-900-PRO, Руководство по данным

Страница: 26 / 61

– – – –
46 47
return dx;
}
/* Function: HumProRead
** Description: This function encodes a read command to the specified
** register address.
*/
unsigned char /* number of encoded bytes, 3 to 4 */
HumProRead(
unsigned char *cmd, /* out: encoded read command, length >= 4 */
unsigned char reg /* register number to read, 0..0xff */
) {
unsigned char ra; /* read register byte */
ra = reg ^ 0x80;
return HumProCommand(cmd, &ra, 1);
}
/* Function: HumProWrite
** Description: This function encodes a command to write a single byte to
** a specified register address.
*/
unsigned char /* number of encoded bytes, 4 to 6 */
HumProWrite(
unsigned char *cmd, /* out: encoded read command, length >= 6 */
unsigned char reg, /* register number to write, 0..0xff */
unsigned char val /* value byte, 0..0xff */
) {
unsigned char cs[2];
cs[0] = reg;
cs[1] = val;
return HumProCommand(cmd, &cs, 2);
}
Example Code for Encoding Read/Write Commands
This software example is provided as a courtesy in “as is” condition. Linx
Technologies makes no guarantee, representation, or warranty, whether
express, implied, or statutory, regarding the suitability of the software for
use in a specific application. The company shall not, in any circumstances,
be liable for special, incidental, or consequential damages, for any reason
whatsoever.
File EncodeProCmd.c
/* Sample C code for encoding Hum-xxx-PRO commands
**
** Copyright 2015 Linx Technologies
** 155 Ort Lane
** Merlin, OR, US 97532
** www.linxtechnologies.com
**
** License:
** Permission is granted to use and modify this code, without royalty, for
** any purpose, provided the copyright statement and license are included.
*/
#include “EncodeProCmd.h”
/* Function: HumProCommand
** Description: This function encodes a command byte sequence.
** If len = 1, a read command is generated.
** If len > 1, a write command is generated.
** rcmd[0] = register number
** rcmd[1..(n-1)] = bytes to write
*/
unsigned char /* number of encoded bytes, n+2 to 2*n+2 */
HumProCommand(
unsigned char *ecmd, /* out: encoded command, length >= 2*n + 2 */
const unsigned char *rcmd, /* in: sequence of bytes to encode */
unsigned char n /* number of bytes in rcmd, 1..32 */
) {
unsigned char dx; /* destination index */
unsigned char sx; /* source index */
unsigned char v; /* value to be encoded */
dx = 2;
sx = 0;
while (n--) {
v = rcmd[sx++];
if (v >= 0xf0) {
ecmd[dx++] = 0xfe;
v &= 0x7f;
}
ecmd[dx++] = v;
}
ecmd[0] = 0xff;
ecmd[1] = dx - 2;