Hello,
I need a SPI running at maximum SPI (32MHz).
My understanding is to have a 32 MHz SPI, I need a core running at 128MHz.
What is the correct way to configure the core clock: (Device Tree? KConfig? nrfx lib?
Thanks
Hello,
I need a SPI running at maximum SPI (32MHz).
My understanding is to have a 32 MHz SPI, I need a core running at 128MHz.
What is the correct way to configure the core clock: (Device Tree? KConfig? nrfx lib?
Thanks
Hi,
SPIM4 is capable of running 32 MHz (regardless of CPU clock freq).
Here's one example from 7002-DK for enabling spi4 (with ext flash):
I need a core running at 128MHz.
You can enable this using the clock control subsys, and call it like this:
https://github.com/nrfconnect/sdk-nrf/blob/v2.5.1/samples/wifi/shell/src/main.c#L57-L62
Kind regards,
Håkon
Hi Hakon,
I've been able to get SPI4 running at 32MHz. But I had to make a couple of manual changes to the SPIM4 register settings manually. It looks like the settings for max-frequency and rx-delay were not being set from the device tree settings.
I had to add this code to get higher than 16MHz running. Without it the frequency was being set to 16MHz and the rx-delay=2. A 30ns delay is way to much at 32MHz.
#include <nrfx_spim.h>
#ifdef NRF_SPIM_HAS_32_MHZ_FREQ
printk("spi has 32MHz\n");
nrf_spim_frequency_set(NRF_SPIM_INST_GET(4), NRF_SPIM_FREQ_32M);
nrf_spim_iftiming_set(NRF_SPIM_INST_GET(4), 0);
#endif
My project is using board nrf5340dk_nrf5340_cpuapp and SDK V2.5.1
My overlay for the SPIM4 setup is
&spi4{
compatible = "nordic,nrf-spim";
status = "okay";
rx-delay = < 0x0 >;
max-frequency = <33000000>;
cs-gpios = <&gpio0 18 GPIO_ACTIVE_LOW>;
w25q64jv: w25q64jv@0 {
compatible = "jedec,spi-nor";
size = <0x4000000>; //8MBytes
spi-max-frequency = <33000000>;
reg = <0>;
jedec-id = [ ef 40 17 ];
wp-gpios = <&gpio0 19 0>;
hold-gpios = <&gpio0 16 0>;
};
};
&spi4_default {
group1 {
psels = <NRF_PSEL(SPIM_SCK, 0, 17)>,
<NRF_PSEL(SPIM_MISO, 0, 14)>,
<NRF_PSEL(SPIM_MOSI, 0, 13)>;
nordic,drive-mode = < 3 >;
};
};
&spi4_sleep {
group1 {
psels = <NRF_PSEL(SPIM_SCK, 0, 17)>,
<NRF_PSEL(SPIM_MISO, 0, 14)>,
<NRF_PSEL(SPIM_MOSI, 0, 13)>;
};
};
which produces .dts output of
spi4: arduino_spi: spi@a000 {
compatible = "nordic,nrf-spim";
#address-cells = < 0x1 >;
#size-cells = < 0x0 >;
reg = < 0xa000 0x1000 >;
interrupts = < 0xa 0x1 >;
max-frequency = < 0x1f78a40 >;
easydma-maxcnt-bits = < 0x10 >;
rx-delay-supported;
rx-delay = < 0x0 >;
status = "okay";
cs-gpios = < &gpio0 0x12 0x1 >;
pinctrl-0 = < &spi4_default >;
pinctrl-1 = < &spi4_sleep >;
pinctrl-names = "default", "sleep";
w25q64jv: w25q64jv@0 {
compatible = "jedec,spi-nor";
size = < 0x4000000 >;
spi-max-frequency = < 0x1f78a40 >;
reg = < 0x0 >;
jedec-id = [ EF 40 17 ];
wp-gpios = < &gpio0 0x13 0x0 >;
hold-gpios = < &gpio0 0x10 0x0 >;
};
};
Which looks to be correct for the what the driver would need to set up the peripheral correctly?
It is interesting to note that I could set the frequency lower than 16MHz with overlay changes.
There seems to be no difference in using either CONFIG_SPI, or CONFIG_SPI_NOR.
Thanks
Simon
Hi Simon,
Sorry, I forgot to mention this. SPIM4 is 32M capable with dedicated pins, as described here:
https://infocenter.nordicsemi.com/topic/ps_nrf5340/spim.html?cp=4_0_0_6_29_6#topic
https://infocenter.nordicsemi.com/topic/ps_nrf5340/chapters/pin.html?cp=4_0_0_8_0
You can see this in the source code as well:
Kind regards,
Håkon
Hi Hakon,
I've just noticed that I'm not using the SPIM4 dedicated pins. I'm using the QSPI pins P0.13, P0.14, P0.16. Everything seems to be working with this setup. I wonder if the driver could be updated to support this? i.e. all the other high drive pins?
I had wired the NOR Flash to the QSPI pins for 2-Bit mode, but it appears the qspi driver only supports 4 bit mode.
(p_config->skip_gpio_cfg && p_config->skip_psel_cfg)
is true in my case which might explain why the frequency and rx-delay were not picked up from the device tree settings.
Regards
Simon
Hi Simon,
QSPI supports both quad, dual, and single mode by declaring these in DT:
Here's an example of them used for quad io operation:
Kind regards,
Håkon