/**
* \brief This function displays information using LEDs about the SHA204 devices
* on the Security Xplained board.
* \param[in] device_present_mask The high nibble represents the four SHA204 devices.
* \param[in] sha204_revision revision of the SHA204 devices
*/
void display_status(uint8_t device_present_mask, uint8_t sha204_revision)
{
uint8_t i;
uint8_t shifter = 1;
// Find out how many devices are present.
for (i = 0; shifter < 0x10; shifter <<= 1)
if (shifter & device_present_mask)
i++;
if (i < SHA204_DEVICE_COUNT) {
// Indicate communication failure.
// Display the devices found using LED4..7 and error using LED0..3.
uint8_t i;
for (i = 0; i < 4; i++) {
led_display_number(~device_present_mask);
sha204h_delay_ms(125);
led_display_number(0);
sha204h_delay_ms(125);
}
}
else {
// Indicate success.
// Display the devices found using LED4..7 and revision of last device using LED0..3.
led_display_number((device_present_mask << 4) | sha204_revision);
sha204h_delay_ms(1000);
led_display_number(0);
sha204h_delay_ms(1000);
}
}
/** \brief This function is the entry function for an example application that
uses the SHA204 ASF component.
* \return result (0: success, otherwise failure)
*/
int main(void)
{
static uint8_t tx_buffer_command[CHECKMAC_COUNT]; // biggest command in this example
static uint8_t rx_buffer[SHA204_RSP_SIZE_MAX];
static uint8_t challenge[MAC_CHALLENGE_SIZE];
static uint8_t other_data[CHECKMAC_OTHER_DATA_SIZE];
uint8_t sha204_lib_return = SHA204_SUCCESS;
uint32_t loop_count = 0;
uint8_t i2c_address_index = 0;
uint8_t twi_address_client;
uint8_t twi_address_host;
// Initialize system clock.
sysclk_init();
// Initialize board.
board_init();
// Initialize logging (USART).
log_init();
// Initialize interrupt vectors.
irq_initialize_vectors();
// Send example info.
log_sha204_title("ATSHA204 Mac / CheckMac Example\r\n");
// Indicate entering main loop.
led_display_number(0xFF);
sha204h_delay_ms(1000);
// The main loop wakes up all four devices, sends a Mac command to one serving
// as a client, and subsequently a CheckMac command with the Mac challenge and response data
// to another SHA204 serving as a host. At the end of the loop, all four devices
// are put back to sleep by sending a Sleep command to every one of them.
while (true) {
// Indicate success or error for some time.
led_display_number(sha204_lib_return);
sha204h_delay_ms(1000);
log_sha204_title("----------------------");
sprintf((char *) tx_buffer_command, "loop count = %lu", loop_count++);
log_sha204_title((char *) tx_buffer_command);
// Indicate that Mac / CheckMac command sequence is running.
led_display_number(0xFF);
// Generate Wakeup pulse. All SHA204 devices that share SDA will wake up.
log_sha204_title("generating 60 us Wakeup low pulse on TWI SDA");
sha204_lib_return = sha204p_wakeup();
if (sha204_lib_return != SHA204_SUCCESS) {
// todo Indicate Wakeup failure.
continue;
}
// Exercise all four devices.
twi_address_client = sha204_i2c_address(i2c_address_index % 4);
i2c_address_index++;
twi_address_host = sha204_i2c_address(i2c_address_index % 4);
i2c_address_index++;
// ---------------------------------------------------------------------------------
// Now let's send a Mac to one SHA204, and verify the generated Mac with a second
// SHA204 serving as a host device. In this example, we are not using the Nonce
// command but the least secure and simplest mode.
// Let host generate a random number to use as Mac challenge. An unlocked SHA204
// will always generate "FFFF0000FFFF0000...".
struct sha204_random_parameters random;
random.mode = 0;
random.tx_buffer = tx_buffer_command;
random.rx_buffer = rx_buffer;
sha204p_set_device_id(twi_address_host);
log_sha204_title("sending Random command to host");
sha204_lib_return = sha204m_random(&random);
log_sha204(random.tx_buffer[SHA204_COUNT_IDX], random.tx_buffer, false);
if (sha204_lib_return != SHA204_SUCCESS) {
sha204_sleep_all();
continue;
}
log_sha204(random.rx_buffer[SHA204_COUNT_IDX], random.rx_buffer, true);
// Save challenge for subsequent CheckMac command.
memcpy(challenge, &random.rx_buffer[SHA204_BUFFER_POS_DATA], sizeof(challenge));
// Send Mac command to client.
struct sha204_mac_parameters mac;
mac.mode = 0;
mac.key_id = 0;
mac.challenge = challenge;
mac.tx_buffer = tx_buffer_command;
mac.rx_buffer = rx_buffer;
sha204p_set_device_id(twi_address_client);
log_sha204_title("sending Mac command to client");
sha204_lib_return = sha204m_mac(&mac);
log_sha204(mac.tx_buffer[SHA204_COUNT_IDX], mac.tx_buffer, false);
if (sha204_lib_return != SHA204_SUCCESS) {
sha204_sleep_all();
continue;
}
log_sha204(mac.rx_buffer[SHA204_COUNT_IDX], mac.rx_buffer, true);
// Save first four bytes of Mac command for subsequent CheckMac command.
memset(other_data, 0, CHECKMAC_OTHER_DATA_SIZE);
memcpy(other_data, &tx_buffer_command[SHA204_OPCODE_IDX], CHECKMAC_CLIENT_COMMAND_SIZE);
// Send CheckMac command to host.
struct sha204_check_mac_parameters check_mac;
check_mac.mode = 0;
check_mac.key_id = 0;
check_mac.client_challenge = challenge;
check_mac.client_response = &rx_buffer[SHA204_BUFFER_POS_DATA];
check_mac.other_data = other_data;
check_mac.tx_buffer = tx_buffer_command;
check_mac.rx_buffer = rx_buffer;
sha204p_set_device_id(twi_address_host);
log_sha204_title("sending CheckMac command to host");
sha204_lib_return = sha204m_check_mac(&check_mac);
log_sha204(check_mac.tx_buffer[SHA204_COUNT_IDX], check_mac.tx_buffer, false);
if (sha204_lib_return != SHA204_SUCCESS) {
sha204_sleep_all();
continue;
}
log_sha204(check_mac.rx_buffer[SHA204_COUNT_IDX], check_mac.rx_buffer, true);
log_sha204_title("sending a Sleep command to all devices");
sha204_sleep_all();
// Display response status byte.
sha204_lib_return = check_mac.rx_buffer[SHA204_BUFFER_POS_STATUS];
}
return sha204_lib_return;
}