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coils: ability to configure number of supported coils

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No change to current default behaviour of allocating 2000 coils.
However memory usage can be reduced by defining NMBS_MAX_COILS.
This commit is contained in:
Spencer Oliver 2025-05-10 16:54:09 +01:00
parent 546040c448
commit d3ac9c1696
2 changed files with 13 additions and 3 deletions
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4
nanomodbus.c
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@ -546,7 +546,7 @@ static nmbs_error recv_read_discrete_res(nmbs_t* nmbs, nmbs_bitfield values) {
uint8_t coils_bytes = get_1(nmbs);
NMBS_DEBUG_PRINT("b %d\t", coils_bytes);
if (coils_bytes > 250) {
if (coils_bytes > NMBS_MAX_COIL_BYTES) {
return NMBS_ERROR_INVALID_RESPONSE;
}
@ -1958,7 +1958,7 @@ nmbs_error nmbs_client_create(nmbs_t* nmbs, const nmbs_platform_conf* platform_c
static nmbs_error read_discrete(nmbs_t* nmbs, uint8_t fc, uint16_t address, uint16_t quantity, nmbs_bitfield values) {
if (quantity < 1 || quantity > 2000)
if (quantity < 1 || quantity > NMBS_MAX_COILS)
return NMBS_ERROR_INVALID_ARGUMENT;
if ((uint32_t) address + (uint32_t) quantity > ((uint32_t) 0xFFFF) + 1)

12
nanomodbus.h
View File

@ -78,11 +78,21 @@ typedef enum nmbs_error {
*/
#define nmbs_error_is_exception(e) ((e) > 0 && (e) < 5)
#ifndef NMBS_MAX_COILS
#define NMBS_MAX_COILS 2000
#endif
/* check coil count divisible by 8 */
#if ((NMBS_MAX_COILS & 7) > 0)
#error "NMBS_MAX_COILS must be disible by 8"
#endif
#define NMBS_MAX_COIL_BYTES (NMBS_MAX_COILS / 8)
/**
* Bitfield consisting of 2000 coils/discrete inputs
*/
typedef uint8_t nmbs_bitfield[250];
typedef uint8_t nmbs_bitfield[NMBS_MAX_COIL_BYTES];
/**
* Bitfield consisting of 256 values