3-Wire SPI Configuration SDK

[maximillion]

Dear Community,

"The functions implemented at the SDK for LPSPI do not have "native support" for 3-wire. So it required to make some changes to support half duplex mode." according to this sentence I have changed to support half duplex mode. I changed to support half duplex mode these functions LPSPI_DRV_MasterInit(..), LPSPI_SetPinConfigMode(..) according to reference manual.

Below is the only information I found in the reference manual about tristate SPI.

According to this information my CFGR1 value is Hex:0x6000001. 

lpspi_pin_config_t pinCfg is = LPSPI_SDO_IN_OUT.

lpspi_data_out_config_t dataOutConfig = LPSPI_DATA_OUT_TRISTATE.

bool pcs3and2Enable = true. 

Please confirm that configuration and CFGR1 value.

Secondly is there any require HW modification like depicted in the below.

Our schematic design does not have a 10K resistor between MOSI and MISO; instead, it has a 0-ohm resistor. MUST there be a 10K or 1K resistor? Please confirm schematic design. 

NOTE: I use S32SDK_S32K1xx_RTM_3.0.0 and S32 Design Studio v2.2 

Also I know

"Included on the RTDs comes an example of SPI half duplex transfer. I suggest you take a look at this software supported by S32DS v3.4.Real-Time Drivers for S32K1" 

[VaneB]

Hi @maximillion 

I answered you in this post

[maximillion]

Hi @VaneB 

Secondly is there any require HW modification like depicted in the below.

Isn't the CFGR1 value the same in all 3-wire SPI configurations? So can you confirm that value? 

Thanks for answering my those questions.

[VaneB]

Hi @maximillion 

The S32K1 does not need to have HW modification, if you configure MOSI as input and output you don have to use any pin for the MISO signal in the PORT module. Also for the other device, the connections depend on its specifications.

Regarding the Configuration Register 1 (CFGR1) value, PINCFG configures SOUT as input and output data, OUTCFG configures the output data as tristated when chip select is negated and PCSCFG configures PCS[3:2] for chip select function. For 3-wire SPI CFGR1 = 0x6000001 is correct, the other bits depend on your application.

[maximillion]

Hi @VaneB 

I'm still confused about TXMSK.
Let me explain my LPSPI0 configuration.
1- I use DMA for SPI configuration and I did not set any RX DMA channel because would transmit and receive data at same channel. I set only TX DMA channel. PS continuous is not selected and and bits/frame value is 9.

So TX DMA channel should receive and transmit data. In that case according to your mention TXMSK should be set. I set TXMSK at the LPSPI_DRV_MasterStartTransfer function. Is this correct?
But when I called LPSPI_DRV_MasterGetTransferStatus it return STATUS_BUSY. This value has not changed any time.

Do you have any advice about this topic?