SM59A16U1
8-Bit Micro-controller
64KB with ISP Flash
& 6K+256B RAM embedded
3.3
Data Memory - Lower 128 Byte( 00h to 7Fh )
Data memory 00h to FFh is the same as 8052.
The address 00h to 7Fh can be accessed by direct and indirect addressing modes.
Address 00h to 1Fh is register area.
Address 20h to 2Fh is memory bit area.
Address 30h to 7Fh is for general memory area.
3.4
Data Memory - Higher 128 Byte( 80h to FFh )
The address 80h to FFh can be accessed by indirect addressing mode.
Address 80h to FFh is data area.
3.5
Data Memory - Expanded 6K Bytes( 0000h ~ 0x17FFh )
From external address 0000h to 17FFh is the on-chip expanded SRAM area, total 6K Bytes. This area can be
accessed by external direct addressing mode (by instruction MOVX).
If the address of instruction MOVX @DPTR is larger then 17FFh, the SM59A16U1 will generate the external memory
control signal automatically.
The address space of instruction MOVX @Ri, i=0, 1 is determined by RCON [7:0] of special function register $86
RCON (internal RAM control register). The default setting of RCON [7:0] is 00h (page0). One page of data RAM is 256
bytes.
When EMEN = 0, the internal 6K expanded RAM is enabled. If access memory space is more than 6K byte, the value
of RCON is sent to Port2 to access external RAM.
When EMEN = 1, the internal 6K expanded RAM is disabled. The value of RCON is invalid and high byte address is
decided by register context of Port2 register P2 [7:0].
MOVX @Ri, A
MOVX A,@Ri
EMEN = 0
EMEN = 1
0
≦
RCON[7:0]
≦
23
Addr [15:8] <= RCON[7:0]
Port2 [7:0] <= P2 [7:0]
24
≦
RCON [7:0]
≦
255
Port2 [7:0] <= P2[7:0]
Port2 [7:0] <= P2 [7:0]
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M071
Ver A
SM59A16U1
04/12/2013
- 31 -
SYNCMOS [ SYNCMOS TECHNOLOGIES,INC ]
