I am trying to program a Microchip MCP4141 digital potentiometer with the STM32CUBEIDE development environment using a NUCLEO F334R8 board. I am sending a 16 bit command through the SPI communications port. When I send the command byte with the data byte, I cannot notice voltage variations between the P0A and P0W terminals of the MCP4141.
Could you help me find the programming error? Thanks
uint8_t data[2];
data[0]=0x00;
data[1]=0x0F;
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4,GPIO_PIN_RESET);
HAL_SPI_Transmit(&hspi1, data, 2, 500);
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4,GPIO_PIN_SET);
Usually when an SPI peripheral does not work, the commands are not received by the slave chip. This can have multiple reasons:
Incorrect wiring (MOSI, MISO, CLK lines)
Incorrect SPI mode (clock phase, clock polarity) --> check SPI settings in CubeMX
Slave chip is in Reset because of incorrect/floating EN or RST Pin
Can you probe the data and clock lines? Do you see a signal being transmitted?
Alternatively, can you successfully read anything from the chips internal memory e.g. the status register?
Related
I am using Waveshare 1.54" ePaper Module. Using SPI peripheral:
CPU freq is 16Mhz
SPI Prescaler DIV by 8
MSB FIRST
CPOL=0, CPHA=1
The Display does not response but it respond with TI CC1310 properly.
The problem with SPI is after transmitting byte it does not go to ideal high state.
I have checked with logic analyser.
The SPI is initialised thus:
/****************** Initializing The SPI Peripheral ******************/
void SPI_setup(void)
{
CLK_PeripheralClockConfig(CLK_PERIPHERAL_SPI, ENABLE); //Enable SPI Peripheral Clock
//Set the MOSI, MISO and SCk at high Level.
//GPIO_ExternalPullUpConfig(GPIOC, (GPIO_Pin_TypeDef)(GPIO_PIN_6),ENABLE);
SPI_DeInit();
SPI_Init(SPI_FIRSTBIT_MSB, //Send MSB First
SPI_BAUDRATEPRESCALER_8, //Fosc/16 = 1MHz
SPI_MODE_MASTER,
SPI_CLOCKPOLARITY_LOW, //IDEAL Clock Polarity is LOW
SPI_CLOCKPHASE_2EDGE, //The first clock transition is the first data capture edge
SPI_DATADIRECTION_2LINES_FULLDUPLEX, //Only TX is Enable
SPI_NSS_SOFT,
0x00);
SPI_Cmd(ENABLE);
}
This is pretty much the same problem you had at Issue in interfacing SPI e-ink display with PIC 18F46K22 only on a different processor. Worth noting that CPHA on STM8 has the opposite sense to CPE on PIC18 which may be the cause of your error. That is to say that CPHA=1 on the STM8 has the same effect as CKE=0 on the PIC18. You really have to look at the timing diagrams for each part carefully.
From https://www.waveshare.com/wiki/1.54inch_e-Paper_Module:
Compare with the STM8 reference manual:
Clearly you need one of:
CPHA=1 / CPOL=1 (SPI_CLOCKPOLARITY_HIGH / SPI_CLOCKPHASE_2EDGE) or
CPHA=0 / CPOL=0 (SPI_CLOCKPOLARITY_LOW / SPI_CLOCKPHASE_1EDGE)
If it is the SCLK that you want to be normally-high, then you need the first option - although I fail to see why that is "ideal", the Waveshare diagram clearly indicates that either is acceptable.
I am working on Atmega328p using Arduino Uno board, my task is SPI comm using register level,
can anybody explain what is meant by DD_MOSI is left shift "1<
I assume you are referring to the code examples on page 172 of the ATmega328p datasheet (http://ww1.microchip.com/downloads/en/DeviceDoc/ATmega48A-PA-88A-PA-168A-PA-328-P-DS-DS40002061A.pdf). In the example, they use DD_MOSI as a stand in for the bit position of the control bit for the pin associated with MOSI signal, which on the MCU in question is PortB[3]. So, when they have the line:
DDR_SPI = (1<<DD_MOSI)|(1<<DD_SCK);
You can translate that to fill in the associated port and bit shifts:
DDRB = (1<<DDB3)|(1<<DDB5); // Since SPI in on Port B, MOSI is the third pin and SCK is the 5th pin, see page 91-92
I have been using ESP32 and writing code in Arduino. However, when I enable Bluetooth, GPIO4 and GPIO15 does not work to read analog inputs. I have connected IR LED's on both pins and reading analog signals. If Bluetooth code is not used, ESP32 is reading the analog signals and displaying it on serial monitor. If the below Bluetooth code is used, the reading is shown as 255 on both pins (reading 5v. Yes, they are 5v for now and will be level shifted to 3.3v).
Can someone please check and suggest a solution?
I have switched the sensors, removed them and whatever I do, the reading is the same when Bluetooth is read
Bluetooth code:
void init_bluetooth() {
ESP_BT.begin("EKA Robot"); //Name of your Bluetooth Signal
Serial.println("Bluetooth Device is Ready to Pair");
}
IR code:
// Read Infrared LED on GPIO4. Similar function exists to read GPIO15
int readIR() {
int sensorValue = analogRead(oaPinL);
delay(5);
sensorValue = map(sensorValue, 0, 4095, 0, 255);
return (sensorValue);
}
I expect to read the sensor values. However, all it shows is 255. Does it mean it is somehow pulled high?
There are two A/D converters in the ESP32 chip, ADC1 and ADC2. ADC2 pins can not be used when Wi-Fi or Bluetooth is used. Pins connected to ADC1 do work. These are GPIO32-36 and GPIO39.
I am facing problems using sc16is750 breakout board. I want to use the interrupt method mentioned in the datasheet. According to which, the IRQ pin should be active low whenever Rx or Tx pins are active, and an Interrupt should be generated.
But the IRQ pin remains high nonetheless. I have set up an external 1k ohm pull-up resistor as mentioned with 3.3v VDD.
My goal is to use vk16e gps module through spi pins on an arduino uno. I have set up the low interrupt on digital pin 2 and it is working fine. If I manually connect this pin to the ground, the gps data appears successfully. But not with the IRQ pin.
I had a similar issue. Finally I found out that the interrupt pin on the breakout board is not connected to the 2kOhm IRQ pull up.
I added a white wire and now it works fine.
i'm experiencing something that bugs me for days, so i am working on the imx6sx cortex m4 side, i have a sensor connected to one of the i2c buses, sensor is set up with data ready on INT1 which is connected to one of the gpios from the MCU. After boot, i configure the sensor so that it outputs data ready interrupt. Note that the i2c works also in interrupt mode, so if i try to read the sensor when the data ready line is asserted i have to wait in the GPIO INT Handler until the i2c transfer is complete in order to get another data ready int and so on.
My problem is that i don't want to wait in the GPIO INT Handler until the i2c transfer is complete, that's why i made the i2c on interrupts too, but if i don't wait in the GPIO Int Handler, something happens to the i2c because the sensor it's not ack the transfer, so i'n not getting other data-ready interrupts.
Please help if you have any idea what could be wrong, also the i2c bus Interrupt has a higher priority than the GPIO interrupt, and unfortunately i can't use a debugger for debugging, only the old-fashioned way, printfs in the console
Thanks
You could use INT1 to trigger a lower priority software interrupt to handle the i2c, then exit freeing the interrupt.
Consider using a RTOS to manage this for you.