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ut372: Break out character-pair decoding to a separate function.

This commit is contained in:
Martin Ling 2015-03-01 22:52:52 +00:00
parent 472bef3990
commit 118268a2fe
1 changed files with 22 additions and 10 deletions
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32
src/dmm/ut372.c
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@ -23,13 +23,14 @@
*/ */
#include <stdlib.h> #include <stdlib.h>
#include <stdint.h>
#include <math.h> #include <math.h>
#include "libsigrok.h" #include "libsigrok.h"
#include "libsigrok-internal.h" #include "libsigrok-internal.h"
#define LOG_PREFIX "ut372" #define LOG_PREFIX "ut372"
char lookup[] = { uint8_t lookup[] = {
0x7B, 0x7B,
0x60, 0x60,
0x5E, 0x5E,
@ -44,6 +45,23 @@ char lookup[] = {
#define DECIMAL_POINT_MASK 0x80 #define DECIMAL_POINT_MASK 0x80
/* Decode a pair of characters into a byte. */
static uint8_t decode_pair(const uint8_t *buf)
{
unsigned int i;
char hex[3];
hex[2] = '\0';
for (i = 0; i < 2; i++) {
hex[i] = buf[i];
if (hex[i] > 0x39)
hex[i] += 7;
}
return strtol(hex, NULL, 16);
}
SR_PRIV gboolean sr_ut372_packet_valid(const uint8_t *buf) SR_PRIV gboolean sr_ut372_packet_valid(const uint8_t *buf)
{ {
return (buf[25] == '\r' && buf[26] == '\n'); return (buf[25] == '\r' && buf[26] == '\n');
@ -52,22 +70,16 @@ SR_PRIV gboolean sr_ut372_packet_valid(const uint8_t *buf)
SR_PRIV int sr_ut372_parse(const uint8_t *buf, float *floatval, SR_PRIV int sr_ut372_parse(const uint8_t *buf, float *floatval,
struct sr_datafeed_analog *analog, void *info) struct sr_datafeed_analog *analog, void *info)
{ {
unsigned int i, j, segments, value, divisor; unsigned int i, j, value, divisor;
char hex[3]; uint8_t segments;
(void) info; (void) info;
hex[2] = '\0';
value = 0; value = 0;
divisor = 1; divisor = 1;
for (i = 0; i < 5; i++) { for (i = 0; i < 5; i++) {
for (j = 0; j < 2; j++) { segments = decode_pair(buf + 1 + 2*i);
hex[j] = buf[2*i + 1 + j];
if (hex[j] > 0x39)
hex[j] += 7;
}
segments = strtol(hex, NULL, 16);
for (j = 0; j < ARRAY_SIZE(lookup); j++) { for (j = 0; j < ARRAY_SIZE(lookup); j++) {
if (lookup[j] == (segments & ~DECIMAL_POINT_MASK)) { if (lookup[j] == (segments & ~DECIMAL_POINT_MASK)) {
value += j * pow(10, i); value += j * pow(10, i);