Communication with CR95HF does not work.
i try to use the nfc reader cr95hf (MIKROE-143) since a few days. as mcu i use the evaluation board nRF52832. unfortunately i don't succeed so far.
The data sheet for the MIKROE-143 can be found here:
https://www.mouser.ch/datasheet/2/272/rfid_click_manual-255532.pdf
I use SPI as communication interface (I set SSI_0 high and SSI_1 low.). According to their datasheet, the CR95HF SPI works in 3 steps:
1. send command
2. poll with 0x03 until SPI return bit 3 to 1
3. send command 0x02 to read
A Control byte is used to specify a communication type and direction:
- 0x00: Send command to the CR95HF
- 0x03: Poll the CR95HF
- 0x02: Read data from the CR95HF
- 0x01: Reset the CR95HF
- The SPI_SS line is used to select a device on the common SPI bus. The SPI_SS pin is active low.
My SPI configuration looks like this:
nrf_drv_spi_config_t spi_config = NRF_DRV_SPI_DEFAULT_CONFIG;
spi_config.ss_pin = NRF_SPI_PIN_NOT_CONNECTED;
spi_config.miso_pin = SPI_MISO_PIN;
spi_config.mosi_pin = SPI_MOSI_PIN;
spi_config.sck_pin = SPI_SCK_PIN;
spi_config.mode = NRF_DRV_SPI_MODE_0;
spi_config.frequency = NRF_DRV_SPI_FREQ_1M;
spi_config.bit_order = NRF_DRV_SPI_BIT_ORDER_MSB_FIRST;
APP_ERROR_CHECK(nrf_drv_spi_init(&spi, &spi_config, spi_event_handler, NULL));The following steps are taken from this data sheet:
http://www.solutions-cubed.com/content/Downloads/Breakout%20Modules/DATASHEET_BM019.pdf
step 1, send the command:
nrf_gpio_pin_clear(SPI_SS_PIN);
spi_xfer_done = false;
APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, invcommand, 5, NULL, 0));
while (!spi_xfer_done){__WFE();}
nrf_gpio_pin_set(SPI_SS_PIN);
nrf_delay_ms(1);step 2, poll for data ready:
nrf_gpio_pin_clear(SPI_SS_PIN);
while(m_rx_buf[0] != 8) {
spi_xfer_done = false;
m_tx_buf[0] = 0x03;
APP_ERROR_CHECK(nrf_drv_spi_transfer(&m_spi_master_0, m_tx_buf, 1, m_rx_buf, 1));
while (!spi_xfer_done) { __WFE(); }
m_rx_buf[0] = m_rx_buf[0] & 0x08;
}
nrf_gpio_pin_set(SPI_SS_PIN);
nrf_delay_ms(1);step 3, read the data:
nrf_gpio_pin_clear(SPI_SS_PIN);
spi_xfer_done = false;
APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, &readcommand, 1, read_buff, sizeof(read_buff)));
while (!spi_xfer_done){__WFE();}
nrf_gpio_pin_set(SPI_SS_PIN);
nrf_delay_ms(1);variable:
uint8_t sendrecv[6] = {0x04, 0x03, 0x26, 0x01, 0x00};
uint8_t invcommand[5] = {0x00, 0x02, 0x02, 0x01,0x21};
uint8_t pollcommand = 0x03;
uint8_t readcommand = 0x02;
uint8_t control_command = 0x00;after step 1:
after step 2:
after step 3:
where does this strange response come from (0x0E 0x00 0x00 0x00 0x00 0x00 0x00 0x00.... 0x00 0x00 0x00 0x00)?
why do i get 0x0E so often?
i kept the startup routine. i checked this with an oscilloscope.
The tag is certainly not empty (checked with my smartphone).