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Stellaris® ARM® Microcontrollers
Stellaris® ARM® LM3S Microcontrollers Forum
LM3S9B96 EPI Connection with 3 External Memories
I'm working on a project using Stellaris LM3S9B96. We have an external RAM, an external Flash and also a dual port memory that is connected between Stellaris and DSP. Now I would like to ask that, how should i configure the CS pins for Stellaris in HW? In EPI registers, there is an option in HostBus16 Mode, use ALE with dual chip select. In this mode EPI 30 is configured as ALE signal, and additionally EPIS27 for CS1(device 1 chip select) and EPIS26 for CS0(device 0 chip select). But in our case, we need 3 CS signals. How should i made the connections?
May i use EPIS25 as CS2, and can I configure the EPI interface just using the ALE functionallity? In this connection, may i apply the Chip Select signals of the external memories using address line decoding?
EPI27 EPI26 EPI25 ActiveDevice
0 1 1 Device 2 active(EPI27 is connected to Device2 CSn pin)
1 0 1 Device 1 active(EPI26 is connected to Device1 CSn pin)
1 1 0 Device 0 active(EPI25 is connected to Device0 CSn pin)
Any help would be appreciated. Thanks for your attention.
I'm close to finish the PCB. So, any answer would be very helpful. I used the CS pins of the external memories as i asked before. Any documentation, any reference design includes more than 2 external devices really helps me.
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