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products:sbc:common:applications:gpio:spi

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products:sbc:common:applications:gpio:spi [2022/07/04 22:26]
hyphop ↷ Links adapted because of a move operation 		products:sbc:common:applications:gpio:spi [2025/02/17 21:40] (current)
nick [Enable SPI]
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-====== SPI ====== 
  
-===== Introduction =====+===== SPI Reference table =====
  
-This document mainly introduces SPI. You will learn how to enable SPI and local loopback testing of SPI.+|           ^  SPI    ^ Pin  ^ Pin name     ^  GPIO name  ^  DT overlay node  ^  Device node     ^ 
 +^  VIM3/3L  |  SPI_B  |  15  | SPIB_SS      |  GPIOH_6    |  spi1             |  /dev/spidev2.1  | 
 +| :::       | :::     |  16  | SPIB_SCLK    |  GPIOH_7    | :::               | :::              | 
 +| :::       | :::     |  35  | SPIB_MISO    |  GPIOH_5    | :::               | :::              | 
 +| :::       | :::     |  37  | SPIB_MOSI    |  GPIOH_4    | :::               | :::              | 
 +^  VIM4     |  SPI_A  |  25  |  SPI_A_SCLK  |  GPIOT_20   |  spi0             |  /dev/spidev1.0  | 
 +| :::       | :::     |  26  |  SPI_A_SS0   |  GPIOT_21   | :::               | :::              | 
 +| :::       | :::     |  36  |  SPI_A_MOSI  |  GPIOT_18   | :::               | :::              | 
 +| :::       | :::     |  37  |  SPI_A_MISO  |  GPIOT_19   | :::               | :::              | 
 +^  VIM1S    |  SPI_A  |  29  |  SPI_A_MOSI  |  GPIOZ_1    | :::               | :::              | 
 +| :::       | :::     |  31  |  SPI_A_CLK   |  GPIOZ_2    | :::               | :::              | 
 +| :::       | :::     |  32  |  SPI_A_MISO  |  GPIOZ_0    | :::               | :::              | 
 +| :::       | :::     |  33  |  SPI_A_SS0   |  GPIOZ_3    | :::               | :::              |
  
-===== Hardware Connection =====+===== Enable SPI =====
  
-Connect the physical pins ''PIN35'' and ''PIN37'' using a DuPont line.+In order to use the SPI, you need to enable the SPI function via [[products:sbc:common:configurations:device-tree-overlay|Device Tree Overlay]].
  
-===== System Configuration =====+<tabbox VIM3/3L/Edge1>
  
-The default SPI is disabled. If you need to use SPI, you can enable it through the overlays function. +Edit ''/boot/env.txt'' to add the SPI node to ''overlays'' node if it doesn't exist.
-```sh +
-$ sudo vim /boot/env.txt +
-``` +
-Modify the overlays part, remove ''pwm_f'' and ''uart3'', and open SPI.+
  
-```diff +Take VIM3 as an example to enable ''SPI_B'', you need to add ''spi1'' node to ''overlays'' node if it doesn't exist. 
-- overlays=uart3 pwm_f i2c3 os08a10 + 
-+ overlays=i2c3 os08a10 spi1+```shell 
 +overlays=spi1
 ``` ```
  
-Reboot to effect. +<WRAP important > 
- +As SPI pins are also used for other function, e.g. UART_C, PWM_F, so that you also need to remove node ''uart3'' and ''pwm_f''.
-<WRAP info > +
-For Overlays documentation, please refer to [[products:sbc:vim4:configurations:device-tree-overlay|Device Tree Overlay]].+
 </WRAP> </WRAP>
  
-SPI configures a loopback test device by default. 
  
-```sh+After reboot, you will see the spi device node. 
 + 
 +```shell
 $ ls /dev/spidev1.1 $ ls /dev/spidev1.1
 /dev/spidev1.1 /dev/spidev1.1
 ``` ```
  
-===== Demo Source Code =====+<tabbox VIM3 with 5.15 kernel>
  
-Get test code+Edit ''/boot/dtb/amlogic/kvim3.dtb.overlay.env'' to add spi node to ''fdt_overlays'' node if it doesn't exist. 
 + 
 + 
 +e.g. Enable ''SPI_B'', you need to add ''spi1'' to node ''fdt_overlays'' if it doesn't exist. 
 + 
 +```shell 
 +fdt_overlays=spi1 
 +``` 
 + 
 +After reboot, you will see the SPI device node. 
 + 
 +```shell 
 +$ ls /dev/spidev2.1  
 +/dev/spidev2.1 
 +``` 
 + 
 +<tabbox VIM3L with 5.15 kernel> 
 + 
 +Edit ''/boot/dtb/amlogic/kvim3l.dtb.overlay.env'' to add spi node to ''fdt_overlays'' node if it doesn't exist. 
 + 
 + 
 +e.g. Enable ''SPI_B'', you need to add ''spi1'' to node ''fdt_overlays'' if it doesn't exist. 
 + 
 +```shell 
 +fdt_overlays=spi1 
 + 
 +``` 
 + 
 +After reboot, you will see the SPI device node. 
 + 
 +```shell 
 +$ ls /dev/spidev2.1  
 +/dev/spidev2.1 
 +``` 
 + 
 +<tabbox VIM4> 
 + 
 +Edit ''/boot/dtb/amlogic/kvim4.dtb.overlay.env'' to add spi node to ''fdt_overlays'' node if it doesn't exist. 
 + 
 + 
 +e.g. Enable ''SPI_A'', you need to add ''spi0'' to node ''fdt_overlays'' if it doesn't exist. 
 + 
 +```shell 
 +fdt_overlays=spi0 
 + 
 +``` 
 + 
 +After reboot, you will see the SPI device node. 
 + 
 +```shell 
 +$ ls /dev/spidev1.0  
 +/dev/spidev1.0 
 +``` 
 +<tabbox VIM1S> 
 + 
 +Edit ''/boot/dtb/amlogic/kvim1s.dtb.overlay.env'' to add spi node to ''fdt_overlays'' node if it doesn't exist. 
 + 
 + 
 +e.g. Enable ''SPI_A'', you need to add ''spi0'' to node ''fdt_overlays'' if it doesn't exist. 
 + 
 +```shell 
 +fdt_overlays=spi0 
 + 
 +``` 
 + 
 +After reboot, you will see the SPI device node. 
 + 
 +```shell 
 +$ ls /dev/spidev1.0  
 +/dev/spidev1.0 
 +``` 
 + 
 +</tabbox> 
 + 
 +===== Disable SPI ===== 
 + 
 +If you want to use normal GPIO instead of SPI, you can remove the SPI node in [[products:sbc:common:configurations:device-tree-overlay|Device Tree Overlay]].  
 + 
 + 
 +===== Demo Source Code =====
  
 ```c spidev_test.c ```c spidev_test.c
Line 72: Line 158:
 } }
  
-static const char *device = "/dev/spidev1.1";+static const char *device = "/dev/spidev1.0";
 static uint32_t mode; static uint32_t mode;
 static uint8_t bits = 8; static uint8_t bits = 8;
Line 521: Line 607:
 ``` ```
  
-Compile test code+Compile test code:
  
-```sh+```shell
 $ gcc -o spidev_test spidev_test.c $ gcc -o spidev_test spidev_test.c
 ``` ```
  
-===== Demonstrate =====+===== Test demonstration =====
  
 +Prepare input text file:
  
-Prepare a TST text file. +```shell
- +
-```sh+
 $ echo "Amazing Khadas!" > ./spi_in.txt $ echo "Amazing Khadas!" > ./spi_in.txt
 ``` ```
  
-Run ''spidev_test''.+Connect PIN36(MOSI), PIN37(MISO) then run ''spidev_test'':
  
-```sh + 
-$ ./spidev_test -i spi_in.txt -o ./spi_out.txt+ 
 +```shell 
 +$ ./spidev_test -D /dev/spidev1.1 -i spi_in.txt -o ./spi_out.txt
 spi mode: 0x0 spi mode: 0x0
 bits per word: 8 bits per word: 8
Line 545: Line 632:
 ``` ```
  
-Check output data. +<WRAP important > 
-```sh+Please choose the correct spi device node. 
 +</WRAP> 
 + 
 + 
 +Check output data: 
 + 
 +```shell
 $ cat ./spi_out.txt $ cat ./spi_out.txt
 Amazing Khadas! Amazing Khadas!
 ``` ```
Last modified: 2022/07/04 22:26 by hyphop

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