3.18 EMIF (not applicable to C5532/33/34/35 or C5545)
EMIF interfaces to both mSDRAM and SDRAM devices that meet the following requirements:
Non-mobile SDRAM can be supported under certain circumstances. The C5504/05/14/15 always use mobile SDRAM initialization but are able to support SDRAM memories that ignore the BA0 and BA1 pins for the load mode register command. During the mobile SDRAM initialization, the device issues the load mode register initialization command to two different addresses that differ in only the BA0 and BA1 address bits. These registers are the Extended Mode register and the Mode register. The extended mode register exists only in mSDRAM and not in non-mSDRAM. If a non-mobile SDRAM memory ignores bits BA0 and BA1, the second loaded register value overwrites the first, leaving the desired value in the mode register and the non-mobile SDRAM will work with the device.
Since the extended load mode register command always occurs before the standard load mode register command, as long as the non-mobile SDRAM ignores BA0 and BA1 during either command, the mode register will first be written to with incorrect (mobile SDRAM) data, then be overwritten with the correct (SDRAM) data.
MT48LC16M4A2 is an example of SDRAM that ignores BA0 and BA1 during the load mode register command
MT48H8M16LF is an example of mobile SDRAM that shows the extended load mode register command before the load mode register command, using BA0 and BA1 to differentiate between the two commands.