LPC55S06 SPI write works, read no!

MarcoGiammarini — Mon, 22 Jan 2024 12:45:38 GMT

Hi,

I am using LPC55S06 to communicate with another microcontroller by using SPI. My microcontroller is the master, the other one is the slave. The configuration is CPOL=0 and CPHA=0, and the datarate is 500kbps. The protocol is 2 byte of register address (with 1 bit that indicate read/write) and 4 byte of data.

When I write a register no problem on my way: the data sniffed with a logic analyzer is perfect, and the slave read data well. When I try to read a register, the slave send out the data, on the logic analyzer the data is perfect, but on microcontroller the last bit will be lost.

In example, if the data that I see on logic analyzer is 0x00000064, on micro I read 0x00000032, and so on. The code that read is the following:

void writeReadRegister (DeviceHandle_t handle, bool readWrite, Register_t addr, uint32_t* message) { uint8_t txData[6]; uint8_t rxData[6]; uint32_t tmpMessage = *message; //readWrite = 1 write if (readWrite == 1) { memset(txData, 0, sizeof(txData)); txData[0] = 0x01; txData[1] = (uint8_t)addr; txData[2] = (uint8_t)((tmpMessage >> 24) & 0x000000FF); txData[3] = (uint8_t)((tmpMessage >> 16) & 0x000000FF); txData[4] = (uint8_t)((tmpMessage >> & 0x000000FF); txData[5] = (uint8_t)(tmpMessage & 0x000000FF); } //readWrite = 0 read else if (readWrite == 0) { memset(txData, 0, sizeof(txData)); txData[0] = 0x00; txData[1] = (uint8_t)addr; memset(rxData, 0, sizeof(rxData)); rxData[0] = 0x00; rxData[1] = (uint8_t)addr; } handle->xferDefault.txData = txData; handle->xferDefault.rxData = rxData; GPIO_PinWrite(handle->gpioPeripheral, handle->port, handle->pin, 0); App_mDelay(1); SPI_MasterTransferBlocking(handle->peripheralNum, &handle->xferDefault); App_mDelay(1); GPIO_PinWrite(handle->gpioPeripheral, handle->port, handle->pin, 1); if (readWrite == 0) { uint32_t temp = 0; temp = (((uint32_t)rxData[5]) & 0x000000FF) | (((uint32_t)rxData[4] << & 0x0000FF00) | (((uint32_t)rxData[3] << 16) & 0x00FF0000) | (((uint32_t)rxData[2] << 24) & 0xFF000000); *message = temp; } }

Where is the error? I can't see!

Thanks

Marco

Re: LPC55S06 SPI write works, read no!

al_bin — Tue, 23 Jan 2024 06:39:40 GMT

Try CPHA=1

Re: LPC55S06 SPI write works, read no!

Alice_Yang — Mon, 29 Jan 2024 02:15:54 GMT

Hello @MarcoGiammarini

How about first use the SPI demo under SDK?

Alice

Re: LPC55S06 SPI write works, read no!

MarcoGiammarini — Thu, 08 Feb 2024 13:49:04 GMT

Hi, I found the problem: the slave device, an FPGA programmed by ourself, generate a wrong MISO message... so the microcontroller can't read well the data.

Thanks all.

LPC MicrocontrollersのトピックRe: LPC55S06 SPI write works, read no!

LPC55S06 SPI write works, read no!

Re: LPC55S06 SPI write works, read no!

Re: LPC55S06 SPI write works, read no!

Re: LPC55S06 SPI write works, read no!