SPI0 Overlap with multiple slaves

[universam1]

Basic Infos

SPI0 Overlap is now #1062 supported, awesome!
I need to address more than one SPI Slave....

Hardware

Hardware: ESP-12-E
Core Version: 2.1.0-rc2

Description

The implementation suggests that there is a possibility to use custom CS thus being able to use more than one SPI slave:
https://github.com/esp8266/Arduino/blob/master/libraries/SPI/SPI.cpp#L129

Question, is this true or the above code does not make sense?

Settings in IDE

Module: Generic ESP8266 Module
Flash Size: 4MB/1MB
CPU Frequency: 80Mhz
Flash Mode: qio
Flash Frequency: 40Mhz
Upload Using: OTA / SERIAL
Reset Method: ?ck

Sketch

 case SPI_PINS_HSPI_OVERLAP:
        if (use) {
...
        }
        else {
            if (useHwCs) {
                pinMode(SPI_OVERLAP_SS, INPUT);
                SPI1P |= SPIPCS1DIS | SPIPCS0DIS | SPIPCS2DIS;
                SPI1U &= ~(SPIUCSSETUP | SPIUCSHOLD);
            }
        }

[universam1]

@riataman Is the SPI overlap transfer blocking? I understand so, so given might it be possible to select the slave prior to the SPI.transfer, by using a simple circuit (AND and NOR) which toggles between these.

I've simulated a circuit I think of here

So the idea is that one custom pin toggles with high/low between two slaves, and the transfer is started by the hardware controlled CS.