What is the correct way to manually select SPIPS device?

[armandas]

Until version 2025.2, I have been using XSpiPs_SetSlaveSelect to manually select my device. This function is not used internally inside embeddedsw, so it seems to me that manual selection would be the main purpose of this function.

However, in 2025.2, in particular commit 2d2965e, adds a guard condition for manual select:

if (XSpiPs_IsManualChipSelect(InstancePtr) == FALSE) {
    /*
        * Read the config register, update the slave select value and write
        * back to config register.
        */
    ConfigReg = XSpiPs_ReadReg(InstancePtr->Config.BaseAddress,
        XSPIPS_CR_OFFSET);
    ConfigReg &= (u32)(~XSPIPS_CR_SSCTRL_MASK);
    ConfigReg |= InstancePtr->SlaveSelect;
    XSpiPs_WriteReg(InstancePtr->Config.BaseAddress, XSPIPS_CR_OFFSET,
        ConfigReg);
}

If XSpiPs_SetSlaveSelect cannot be used for manual selection, what is the purpose of this function? And which API am I supposed to use for manual selection?

[akumarma129]

Hello @armandas,

The primary purpose of XSpiPs_SetSlaveSelect() is to update InstancePtr->SlaveSelect with the appropriate chip‑select (CS) value. In manual mode, the actual slave selection—i.e., programming the CS value into the CONFIG register—is handled here in XSpiPs_Transfer().

For manual chip selection, the correct and supported approach is to enable the appropriate SPI options using XSpiPs_SetOptions().
In manual mode, chip‑select is controlled via the FORCE‑SSELECT mechanism.During the the transfer driver takes care of chip selection/deselection.
example:

/* Configure options: master mode + manual CS */
XSpiPs_SetOptions(&SpiInstance,
XSPIPS_MASTER_OPTION | XSPIPS_FORCE_SSELECT_OPTION);

The referenced patch addresses a timing issue and also restricts the slave‑select operation in XSpiPs_SetSlaveSelect() to auto mode only, since in manual mode XSpiPs_Transfer() already contains the logic to select the slave.

Regards,
Amit