Datasheet

71M6533/G/H and 71M6534/H Data Sheet FDS_6533_6534_004
20 Rev 2
If the MPU overwrites the CE’s working RAM, the CE’s output may be corrupted. If the CE is
disabled, the first 0x40 bytes of RAM are still unusable while MUX_DIV[3:0] ≠ 0 because the
71M6533/71M6534 ADC writes to these locations. Setting MUX_DIV[3:0] = 0 disables the ADC
output, preventing the CE from writing the first 0x40 bytes of RAM.
The 80515 writes into external data memory when the MPU executes a MOVX @Ri,A or MOVX
@DPTR,A instruction. The MPU reads external data memory by executing a MOVX A,@Ri or MOVX
A,@DPTR instruction (SFR PDATA provides the upper 8 bytes for the MOVX A,@Ri instruction).
Internal and External Memory Map
Table 7 shows the address, type, use and size of the various memory components.
Only the memory ranges shown in Table 7 contain physical memory.
Table 7: Memory Map
Address
(hex)
Memory
Technology
Memory
Type
Name Typical Usage
Memory Size
(bytes)
00000-1FFFF Flash Memory
Non-
volatile
Program memory
MPU Program and
non-volatile data
128 KB
00000-3FFFF
†
Flash Memory
Non-
volatile
Program memory
MPU Program and
non-volatile data
256 KB
†
on 1K
boundary
Flash Memory
Non-
volatile
Program memory CE program 8 KB max.
0000-0FFF Static RAM Volatile
External RAM
(XRAM)
Shared by CE and
MPU
4 KB
2000-20BF,
20C8-20FF
Static RAM Volatile
Configuration RAM
(I/O RAM)
Hardware control 256
20C0-20C7 Static RAM
Non-
volatile
(battery)
Configuration RAM
(I/O RAM)
Battery-buffered
memory
8
0000-00FF
Static RAM
Volatile
Internal RAM
Part of 80515 Core
256
†
For the 71M6534 only.
MOVX Addressing
There are two types of instructions differing in whether they provide an 8-bit or 16-bit indirect address to
the external data RAM.
In the first type, MOVX A,@Ri, the contents of R0 or R1 in the current register bank provide the eight
lower-ordered bits of address. The eight high-ordered bits of the address are specified with the PDATA
SFR. This method allows the user paged access (256 pages of 256 bytes each) to all ranges of the
external data RAM.
In the second type of MOVX instruction, MOVX A,@DPTR, the data pointer generates a 16-bit address.
This form is faster and more efficient when accessing very large data arrays (up to 64 KB), since no
additional instructions are needed to set up the eight high ordered bits of the address.
It is possible to mix the two MOVX types. This provides the user with four separate data pointers, two
with direct access and two with paged access, to the entire 64 KB of external memory range.
Dual Data Pointer
The Dual Data Pointer accelerates the block moves of data. The standard DPTR is a 16-bit register that
is used to address external memory or peripherals. In the 80515 core, the standard data pointer is called
DPTR, the second data pointer is called DPTR1. The data pointer select bit, located in the LSB of the DPS
register (DPS[0]), chooses the active pointer. DPTR is selected when DPS[0] = 0 and DPTR1 is selected
when DPS[0] = 1.