Resource allocation

[ran]

Hi, 

for my nrf52840 based project, I need to following peripherals :

 2 X SPIM Master

2 TWIM Master

1X TWIS Slave 

Given the resource sharing constraint, is this configuration even possible? 

if yes , is there a recommended configuration ? ( which SPI ID's to use for ex. )

Ran 

[awneil]

Surely, the Product Specification tells you how many SPI and TWI hardware modules are available?

ran said:

2 TWIM Master

Why do you need two?

The whole point of TWI as a bus is that it one Master can communicate with multiple Slaves.

Similarly for SPI although, being less well defined, some peripherals might not play nicely together

[ran]

Thanks. 

I have one TWIM routed to an outside connector and another one to on-board Slave ( RTC \ EEPROM ) 

Should I enable PRS module to over-come resource sharing conflict  ? 

[awneil]

I2C isn't really intended to off-board connections.

Note that you can get TWI multiplexers & bridges ...

PRS won't help if the chip doesn't have the required number of hardware devices.

[ran]

The I2C is going to an FPGA and from there multiplexed. 

What do you mean by "required number of hardware devices" ? We are using nrf52840 chip 

[awneil]

ran said:

What do you mean by "required number of hardware devices" ?

A TWI controller is a physical bit of hardware on the silicon.

Likewise SPI.

The nRF52840 (like any other microcontroller) has a finite and fixed number of these physical bits of hardware on the silicon.

The Product Specification tells you what the number is.