Samsung KS57C2308 Manual page 34

ADDRESSING MODES
ENABLE MEMORY BANK SETTINGS
EMB = "1"
When the enable memory bank flag EMB is set to logic one, you can address the data memory bank specified by
the select memory bank (SMB) value (0, 1 or 15) using 1-, 4-, or 8-bit instructions. You can use both direct and
indirect addressing modes. The addressable RAM areas when EMB = "1" are as follows:
If SMB = 0, 000H–0FFH
If SMB = 1, 100H–1FFH
If SMB = 15, F80H–FFFH
EMB = "0"
When the enable memory bank flag EMB is set to logic zero, the addressable area is defined independently of
the SMB value, and is restricted to specific locations depending on whether a direct or indirect address mode is
used.
If EMB = "0", the addressable area is restricted to locations 000H–07FH in bank 0 and to locations F80H–FFFH
in bank 15 for direct addressing. For indirect addressing, only locations 000H–0FFH in bank 0 are addressable,
regardless of SMB value.
To address the peripheral hardware register (bank 15) using indirect addressing, the EMB flag must first be set to
"1" and the SMB value to "15". When a
address 0000H.
EMB-Independent Addressing
At any time, several areas of the data memory can be addressed independent of the current status of the EMB
flag. These exceptions are described in Table 3-1.
Address
000H–0FFH
FB0H–FBFH
FF0H–FFFH
FC0H–FFFH
3-4
RESET
Table 3-1. RAM Addressing Not Affected by the EMB Value
Addressing Method
4-bit indirect addressing using WX
and WL register pairs;
8-bit indirect addressing using SP
1-bit direct addressing
1-bit indirect addressing using the
L register
occurs, the EMB flag is set to the value contained in bit 7 of ROM
Affected Hardware
Not applicable
PSW, SCMOD,
IEx, IRQx, I/O
BSC, I/O
KS57C2308/P2308/C2316/P2316
Program Examples
LD A,@WX
PUSH EA
POP EA
BITS EMB
BITR IE4
BTST FC3H.@L
BAND C,P3.@L