User’s Manual
3-5
05.99
Memory Organization
C513AO
3.5
Special Function Registers
The registers reside in the special function register area, with the exception of the Program Counter
and the four General Purpose Register banks. The special function register area consists of two
portions: the
standard
special function register area and the
mapped
special function register area.
Four special function registers of the C513AO (PCON1, VR0, VR1 & VR2) are located in the
mapped special function register area. For accessing the mapped special function register area, bit
RMAP in special function register SYSCON must be set. All other special function registers of the
C513AO are located in the standard special function register area.
Special Function Register SYSCON (Address B1
H
)
Reset Value: XX10XXX0
B
If bit RMAP is set, mapped special function registers can be accessed. This bit is not cleared by
hardware automatically.
The forty Special Function Registers (SFRs) in the standard and mapped SFR area include pointers
and registers that provide an interface between the CPU and the other on-chip peripherals. The
SFRs of the C513AO are listed in Table 3-1 and Table 3-2. In Table 3-1, they are organized in
groups which refer to the functional blocks of the C513AO. Table 3-2 illustrates the contents of the
SFRs in numeric order of their addresses.
Bit
Function
EALE
Enable ALE Output
EALE = 0: ALE generation is disabled during internal code memory
accesses (EA = 1) ; ALE is generated during MOVX
instructions.
EALE = 1: ALE generation is enabled.
If EA = 0, the ALE generation is always enabled and the bit EALE has no
effect on ALE generation.
RMAP
Special function Register MAP bit
RMAP = 0: The access to the non-mapped (standard) special function
register area is enabled.
RMAP = 1: The access to the mapped special function register area is
enabled.
XMAP
Global XRAM MAP access enable/disable control
XMAP = 0: On-chip XRAM disabled (default after reset).
XMAP = 1: On-chip XRAM enabled.
–
Reserved for future use. Read by CPU; returns undefined values.
7
6
5
4
3
2
1
0
EALE
RMAP
–
B1
H
SYSCON
Bit No.
MSB
LSB
–
–
–
–
XMAP
