Hello all, I'm trying to get an SAMD21G18A to write to an MCP4131 digipot. I tired the asf code example for SPI but it is not working. Where am I going wrong?
/*
* File: Main.c
* Author: Armstrong Subero
* Controller: SAMD21G18A w/INT OSC @ 48 MHz 3.3v
* Program: 01_Pushbutton
* Compiler: ARM/GNU (v 5.3.1, Atmel Studio v7.0)
*
* Program Version: 1.0
* * Added:
* * Issues:
*
*
* Program Description: Turns on an LED when a pushbutton is pressed
*
* Hardware Description: An LED is connected via a 1k resistor to PIN PA23 and a Pushbutton connected to PIN_PB23 10K pullup
*
* Created on November, 1st , 2016, 1:13 PM
*/
/*******************************************************************************
*Includes and defines
*******************************************************************************/
// Atmel Software Framework
#include <asf.h>
#include <stdio.h>
#include <stdlib.h>
#define LED_0_PIN PIN_PA23
#define SW_0_PIN PIN_PB23
#define SLAVE_SELECT_PIN PIN_PA16
struct spi_module spi_master_instance;
struct spi_slave_inst slave;
void configure_spi_master(void);
void digipot_write(uint8_t data);
/*******************************************************************************
* Function: void config_pins(void)
*
* Returns: Nothing
*
* Description: Configures IO Pins
*
*******************************************************************************/
static void config_pins(void)
{
// General Pin config
struct port_config config_port_pin;
port_get_config_defaults(&config_port_pin);
// Pushbutton Config
config_port_pin.direction = PORT_PIN_DIR_INPUT;
config_port_pin.input_pull = PORT_PIN_PULL_UP;
port_pin_set_config(SW_0_PIN, &config_port_pin);
// LED Config
config_port_pin.direction = PORT_PIN_DIR_OUTPUT;
port_pin_set_config(LED_0_PIN, &config_port_pin);
}
void configure_spi_master(void)
{
struct spi_config config_spi_master;
struct spi_slave_inst_config slave_dev_config;
/* Configure and initialize software device instance of peripheral slave */
spi_slave_inst_get_config_defaults(&slave_dev_config);
slave_dev_config.ss_pin = SLAVE_SELECT_PIN;
spi_attach_slave(&slave, &slave_dev_config);
/* Configure, initialize and enable SERCOM SPI module*/
config_spi_master.mux_setting = SPI_SIGNAL_MUX_SETTING_A;
config_spi_master.mode_specific.master.baudrate = 1000000;
config_spi_master.pinmux_pad0 = PINMUX_PA04D_SERCOM0_PAD0;
config_spi_master.pinmux_pad1 = PINMUX_PA05D_SERCOM0_PAD1;
config_spi_master.pinmux_pad2 = PINMUX_UNUSED;
config_spi_master.pinmux_pad3 = PINMUX_UNUSED;
spi_init(&spi_master_instance, SERCOM0, &config_spi_master);
spi_enable(&spi_master_instance);
}
void digipot_write(uint8_t data)
{
uint8_t data2 = 0x00;
// set CS low
spi_select_slave(&spi_master_instance, &slave, false);
spi_write_buffer(&spi_master_instance, data2,1);
spi_write_buffer(&spi_master_instance, data,1);
// set CS high
spi_select_slave(&spi_master_instance, &slave, true);
}
/*******************************************************************************
* Function: int main(void)
*
* Returns: Nothing
*
* Description: Initializations for main
*
*******************************************************************************/
int main(void)
{
system_init();
config_pins();
configure_spi_master();
while (true) {
digipot_write(100);
delay_ms(500);
}
return 0;
}
