Part Number: TMS320C6747
In our design there is already a connection from C6747 to an UART, starting with both EMA_BA:
EMA_BA to A, EMA_BA to A, EMA_A to A and so on. This is working.
I want to make a further connection to an SRAM (MT48LC16M8A2) with the same 16 bit data at EMIF A. In SPRUFL6D.EMIF.PDF I can see at page 26, that in case of 16 bit data A should be connected to EMA_BA and A to EMA_A and so on, but there they are talking about asynchronous RAM.
In an example from Spectrum Digital I find an 1-to-1 connection (A[0-12] and BA[0-1]).
I got confused about starting with EMA_BA (one or both bits) or EMA_A. If I must change our existing connection, I'll got in trouble with the existing UART. Hopefully I can connect to the SRAM starting with EMA_BA[0-1] like before, but SPRUFL6D.EMIF.PDF says this is for 8 bit data and asynchronous interfaces.
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In reply to RandyP:
many thanks for the fast reply.
Unfortunately, we have the EMIF B not accessible. We use nearly all GPIOs.
I don't understand, if connecting an SDRAM with 16 bit I necessarily need to connect as page 26 in SPRUFL6D.EMIF.PDF. That means:
A - EMA_BA
A - EMA_A
What happens if I connect an SDRAM this way (as we have with the UART):
A - EMA_BA
A - EMA_A
Maybe there is no problem. All of the Micron variants
MT48LC32M4A2 – 8 Meg x 4 x 4 BanksMT48LC16M8A2 – 4 Meg x 8 x 4 BanksMT48LC8M16A2 – 2 Meg x 16 x 4 Banks
show the same address pinning with BA, BA, A, A...
The connection with both BA pins seems to be due to another interface, this time 8 bit (Anybus). It works well with the other 16 bit interface (UART). So I think, with the SDRAM there will be no problem.
Kind regards, Pablo
In reply to Pablo Holtkamp:
I think that now all interfaces are documented in the C6747 TRM - SPRUH91D from Sept 2016:http://www.ti.com/lit/ug/spruh91d/spruh91d.pdf
This would be page 700 Fig 18-3/18.4 and Table 18-6 for address connection.
In reply to AnBer:
many thanks for your help.
I have to explain more about our project. It already existed with several adress/data interfaces:
Anybus with 8 bit data, 2 x UART with 8 bit data and Ethernet controller with 8 bit data.
At the beginning we had only 8 bit data, therefore we connected both BA pins with A and A.
Last year we changed the ethernet controller to another with 16 bit data. This device (wiznet W5300) can operate in 8 bit and 16 bit mode. It ignores the LSB A when operated in 16 bit mode. Everything works fine.
With this configuration, we are using 3 of the 5 CS pins for our interfaces.
And now we want to communicate with an SDRAM, in 16 bit mode.
SDRAMs need a special connection, as you mentioned. We must reconfigure the EMIF interface, making osolete 2 of our CS pins. Unfortunately, these CS (now RAS) and CS (now CAS) pins are not reconfigurable at other pins. We have to help ourselves with GPIOs.
I think our problem is solved. Whether it works or not, we will see in a half years time, when we have the new board.
Now I try to close the case.
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