AHB/APB

I'm not sure that either protocol actually limits the number of slaves. Where did you see this described ?

I know that the original AHB protocol limited the number of AHB masters to 16, the reason being that AHB only supported one active master at a time, so if you had 15 or more other masters waiting to use that single bus you really should be looking at a different system architecture to improve performance and reduce latency for the other masters.

AHB-lite obviously only supports just one master on the bus, so no "16" maximum there.

For the number of slaves, there shouldn't be a limit. Connect however many you need for your application. Just remember that more slaves means a more complex AHB address decoder, so potentially starting to add a critical combinatorial timing path from HADDR to HSEL. But for APB the HSEL-PSEL timing is registered, so no reason to have any limit on the number of APB devices.

Please describe where you saw the slave number limit described so I can comment (if I can).

I'm not sure that either protocol actually limits the number of slaves. Where did you see this described ?

I know that the original AHB protocol limited the number of AHB masters to 16, the reason being that AHB only supported one active master at a time, so if you had 15 or more other masters waiting to use that single bus you really should be looking at a different system architecture to improve performance and reduce latency for the other masters.

AHB-lite obviously only supports just one master on the bus, so no "16" maximum there.

For the number of slaves, there shouldn't be a limit. Connect however many you need for your application. Just remember that more slaves means a more complex AHB address decoder, so potentially starting to add a critical combinatorial timing path from HADDR to HSEL. But for APB the HSEL-PSEL timing is registered, so no reason to have any limit on the number of APB devices.

Please describe where you saw the slave number limit described so I can comment (if I can).