Ok, my tests are OK on the prototype board.
Here are the module features :
– Reference TE-1508
– 512KB of static RAM
– 16 pages of 32KB located in the ME1 zone
– Software selection of the page
– Software Activation/Desactivation (for example the IWS video interface uses same zone in ME1)
– Optional CR-2032 backup battery
– Optional write protection by jumper.
The page selection uses a very special feature of the LH5801 processor which was never being used before… because Sharp never routed this pin !
The data bus can work as a multiplexed bus like the Intel 8052 from the MCS51 family. It means that at one time data are on the bus and another time it’s something else. And this is f… good feature ! I don’t have to use many logical cells. Page 42 of the Technical Reference Manual describe it as the ATP instruction. It pushes the accumulator value on the data bus and provides all signals to store it in a latch. And here we just have to plug an octal latch.
I need some tests with the final board and i will tell you the price…
Is it enough to store your programs ? 😀