#160298 - tasteforreality - Sun Jul 13, 2008 8:36 pm
OK, ive been reading up the info from various sources and reminding myself of all the micro processor stuff i wasnt meant to have learnt during my time at university and i think im getting the hang of this whole understanding slot 2 thing.
i have a few queries and questions id like to get answered now and then i think im going to bury myself in some actual soldering.
as i understand it there are two different modes that can be used. one for accessing a GBA cart ROM, the other for accessing the carts SRAM.
when used to access a cart ROM,CS will initially be high.AD0 to AD15 and A16 to A23 are all address line outputs. on the falling edge of CS, the GBA cart will internally latch the values of AD0 to AD15, it will then send the 16bit data value to AD0/AD15 for the DS to read.
the DS will then take CS high and either the DS can put another address there or the GBA cart will increment the address itself based on the happenings of RD and WR.
in the other mode used for accessing SRAM, AD0 to AD15 are used for the address and A16 to A23 are used to read this in.
so to ask questions finally, is the above correct? where do WR and RD actually come into it?
further more, if im going to create an interface between the real world and the DS, would i be able to do it by having a central block of memory whereby the DS writes to and reads from this memory, and a seperate micro controller interfaces between the memory and the real world.
if this is the way to go about it what do i need to worry about (im guessing that having the external controller and the DS try to do things to the memory at the same time is bad) and how can i avoid these things.
if this isnt the best way then what should i do?
cheers very much to anybody who can help me out with all of this
i have a few queries and questions id like to get answered now and then i think im going to bury myself in some actual soldering.
as i understand it there are two different modes that can be used. one for accessing a GBA cart ROM, the other for accessing the carts SRAM.
when used to access a cart ROM,CS will initially be high.AD0 to AD15 and A16 to A23 are all address line outputs. on the falling edge of CS, the GBA cart will internally latch the values of AD0 to AD15, it will then send the 16bit data value to AD0/AD15 for the DS to read.
the DS will then take CS high and either the DS can put another address there or the GBA cart will increment the address itself based on the happenings of RD and WR.
in the other mode used for accessing SRAM, AD0 to AD15 are used for the address and A16 to A23 are used to read this in.
so to ask questions finally, is the above correct? where do WR and RD actually come into it?
further more, if im going to create an interface between the real world and the DS, would i be able to do it by having a central block of memory whereby the DS writes to and reads from this memory, and a seperate micro controller interfaces between the memory and the real world.
if this is the way to go about it what do i need to worry about (im guessing that having the external controller and the DS try to do things to the memory at the same time is bad) and how can i avoid these things.
if this isnt the best way then what should i do?
cheers very much to anybody who can help me out with all of this