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mhz19: use the same length for request and reply

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per spec request and response are of the same length,
simplify code by using the same length buffers. It should
help later when more code that uses buffers are added.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
This commit is contained in:
Igor Mammedov 2019-05-23 21:14:40 +02:00
parent ceec15dfed
commit 57ff465d39
1 changed files with 6 additions and 8 deletions
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14
esphome/components/mhz19/mhz19.cpp
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@ -5,20 +5,19 @@ namespace esphome {
namespace mhz19 {
static const char *TAG = "mhz19";
static const uint8_t MHZ19_REQUEST_LENGTH = 8;
static const uint8_t MHZ19_RESPONSE_LENGTH = 9;
static const uint8_t MHZ19_COMMAND_GET_PPM[] = {0xFF, 0x01, 0x86, 0x00, 0x00, 0x00, 0x00, 0x00};
static const uint8_t MHZ19_PDU_LENGTH = 9;
static const uint8_t MHZ19_COMMAND_GET_PPM[] = {0xFF, 0x01, 0x86, 0x00, 0x00, 0x00, 0x00, 0x00, 0x79};
uint8_t mhz19_checksum(const uint8_t *command) {
uint8_t sum = 0;
for (uint8_t i = 1; i < MHZ19_REQUEST_LENGTH; i++) {
for (uint8_t i = 1; i < MHZ19_PDU_LENGTH - 1; i++) {
sum += command[i];
}
return 0xFF - sum + 0x01;
}
void MHZ19Component::update() {
uint8_t response[MHZ19_RESPONSE_LENGTH];
uint8_t response[MHZ19_PDU_LENGTH];
if (!this->mhz19_write_command_(MHZ19_COMMAND_GET_PPM, response)) {
ESP_LOGW(TAG, "Reading data from MHZ19 failed!");
this->status_set_warning();
@ -51,14 +50,13 @@ void MHZ19Component::update() {
}
bool MHZ19Component::mhz19_write_command_(const uint8_t *command, uint8_t *response) {
this->write_array(command, MHZ19_REQUEST_LENGTH);
this->write_byte(mhz19_checksum(command));
this->write_array(command, MHZ19_PDU_LENGTH);
this->flush();
if (response == nullptr)
return true;
bool ret = this->read_array(response, MHZ19_RESPONSE_LENGTH);
bool ret = this->read_array(response, MHZ19_PDU_LENGTH);
return ret;
}
float MHZ19Component::get_setup_priority() const { return setup_priority::DATA; }