SPIM

RE: SPIM

Kazi Afroza Sultana — Fri, 29 May 2026 09:40:01 GMT

Hello,

Yes. you are right. When speed is as high as 32Mbps, normal GPIO routing is not fast enough or clean enough electrically. That's why SPIM4 has dedicated physical pins for SPIM4 that bypass the normal GPIO matrix. Only SPIM4 has hardware controlled CS.

RE: SPIM

Petar02 — Thu, 28 May 2026 11:04:57 GMT

Yea, what i meant is that for nrf5340 only SPIM4 with dedicated pins can control CS, others dont have hardver enable CS control, I had manualy to set CS low for SPIM transfer.

RE: SPIM

Kazi Afroza Sultana — Thu, 28 May 2026 10:06:34 GMT

Can you please explain what did you mean here?

SPIM4 is the only instance supporting up to 32 Mbps, but this is not directly related to the EVENTS_END never being set issue. have you tried the example code I showed before?

RE: SPIM

Petar02 — Fri, 08 May 2026 16:22:23 GMT

Yes u are right but only for SPIM4 or this is wrong?

RE: SPIM

Kazi Afroza Sultana — Fri, 08 May 2026 14:02:03 GMT

Hello,

You need to configure CSN pin as output in the GPIO peripheral with intial value high before enabling SPIM. source:SPIM — Serial peripheral interface master with EasyDMA

The key points here is to configure GPIO before SPIM is enabled and to set PSEL registers while SPIM is disabled. So , your approach is correct now.

For example something like below code (based on your code in first thread)

// 1. Make sure SPIM is disabled first
SPI_DAC->ENABLE = SPIM_ENABLE_ENABLE_Disabled;

// 2. Configure GPIO pins BEFORE enabling SPIM
// SCK - output, initial value same as CPOL (0 for Mode 0)
nrf_gpio_pin_clear(NRF_GPIO_PIN_MAP(0, 29));
nrf_gpio_cfg_output(NRF_GPIO_PIN_MAP(0, 29));

// MOSI - output, initial value 0
nrf_gpio_pin_clear(NRF_GPIO_PIN_MAP(1, 10));
nrf_gpio_cfg_output(NRF_GPIO_PIN_MAP(1, 10));

// CSN - output, initial value 1 (deasserted/high)
nrf_gpio_pin_set(CSPIN);
nrf_gpio_cfg_output(CSPIN);

// 3. Configure PSEL registers while SPIM is still disabled
SPI_DAC->PSEL.SCK  = NRF_GPIO_PIN_MAP(0, 29);
SPI_DAC->PSEL.MOSI = NRF_GPIO_PIN_MAP(1, 10);
SPI_DAC->PSEL.MISO = NRF_SPIM_PIN_NOT_CONNECTED;
SPI_DAC->PSEL.CSN  = CSPIN;  // SPIM will now control CS automatically

// 4. Configure frequency and SPI mode
SPI_DAC->FREQUENCY = SPIM_FREQUENCY_FREQUENCY_M8 << SPIM_FREQUENCY_FREQUENCY_Pos;
SPI_DAC->CONFIG =
    (SPIM_CONFIG_ORDER_MsbFirst  << SPIM_CONFIG_ORDER_Pos) |
    (SPIM_CONFIG_CPOL_ActiveHigh << SPIM_CONFIG_CPOL_Pos)  |
    (SPIM_CONFIG_CPHA_Leading    << SPIM_CONFIG_CPHA_Pos);  // Mode 0

// 5. Set up DMA buffers
SPI_DAC->TXD.LIST   = 0;
SPI_DAC->RXD.LIST   = 0;
SPI_DAC->TXD.PTR    = (uint32_t)&dac_tx_buf;
SPI_DAC->TXD.MAXCNT = 2;
SPI_DAC->RXD.PTR    = 0;
SPI_DAC->RXD.MAXCNT = 0;  // No RX needed for DAC

// 6. Enable SPIM
SPI_DAC->ENABLE = SPIM_ENABLE_ENABLE_Enabled;

// 7. Start transfer - SPIM will automatically:
//    - Pull CSN low
//    - Clock out data on MOSI
//    - Pull CSN high when done
SPI_DAC->EVENTS_END = 0;
SPI_DAC->TASKS_START = 1;

while (!SPI_DAC->EVENTS_END) { /* wait */ }
SPI_DAC->EVENTS_END = 0;

RE: SPIM

Petar02 — Wed, 06 May 2026 12:12:06 GMT

Yea i did. But now i saw what the problem is. On nrf5340 CSN is not supported, only for SPIM4 on dedicated pin.

RE: SPIM

Kazi Afroza Sultana — Wed, 06 May 2026 12:08:02 GMT

Hello,

Did you delete your previous message about solving the issue? I will look for it now.

RE: SPIM

Petar02 — Wed, 06 May 2026 10:12:04 GMT

Im using logic analyzer. I saw that i disabled by accident a spim, after fixing that i now see SCLK MOSI generating, but still have problem with CS. If i do this SPI_DAC->PSEL.CSN = CSPIN; does than SPIM controls CS, with task start will he put pin low and after transfer put it high ?

RE: SPIM

Turbo J — Wed, 06 May 2026 09:49:14 GMT

I recommend using an oscilloscope.

The SPIM units have the quirk that they require to "see" level changes on the SCK pin and will stop (and not produce end event) otherwise.

Its very easy to overlook a pin being used elsewhere in the DTS or being forwarded to the net core.

RE: SPIM

Petar02 — Wed, 06 May 2026 08:34:27 GMT

I tried that but its the same. Im using two SPIMs one for DAC and one for ADC.

Same code that Im using I have used for ADC but on nrf52480 and there works fine, also there i was manually setting CS pin and tried that on nrf5340. I done what u suggested but it stil doesnt work properly.

RE: SPIM

hmolesworth — Tue, 05 May 2026 17:23:15 GMT

Maybe try disabling SPIM before setting up the pins:

  // Manual says disable SPI before changing pins, but actually doesn't matter
  NRF_DAC0->ENABLE = 0;               // disable SPI
  
  // Set up pins here
  
  NRF_DAC0->ENABLE = 7;               // enable SPI

Also use an actual pin for CSN (if using SPIM to drive CSN) and be sure to set pin output mode:

This won't work:
  SPI_DAC->PSEL.CSN = NRF_SPIM_PIN_NOT_CONNECTED;
  
  Maybe try something like:
  NRF_GPIO->PIN_CNF[CSPIN]   = 0x301;  // output, high drive high and low H0H1
  NRF_GPIO->PIN_CNF[SCKPIN]  = 0x301;  // output, high drive high and low H0H1
  NRF_GPIO->PIN_CNF[MOSIPIN] = 1;      // output, standard drive S0S1
  SPI_DAC->PSEL.CSN = CSPIN;
  SPI_DAC->PSEL.SCK = NRF_GPIO_PIN_MAP(0, 29);
  SPI_DAC->PSEL.MOSI = NRF_GPIO_PIN_MAP(1, 10);

RE: SPIM

Petar02 — Tue, 05 May 2026 12:58:55 GMT

Sorry same problem stil.