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Datapointer, SFR Address 082 H and 083 H
The 16-bit Datapointer (DPTR) register is a concatenation of registers DPH (data pointer's high
order byte) and DPL (data pointer's low order byte). The data pointer is used in register-indirect
addressing to move program memory constants and external data memory variables, as well as to
branch within the 64 Kbyte program memory address space.
Ports 0 to 5
P0 to P5 are the SFR latches to port 0 to 5, respectively. The port SFRs 0 to 5 are bit-addressable.
Ports 0 to 5 are 8-bit I/O ports (that is in total 48 I/O lines) which may be used as general purpose
ports and which provide alternate output functions dedicated to the on-chip peripherals of the SAB
80(C)515.
Port 6 (AN0 to AN7)
In the MYMOS versions, the analog input lines AN0 to AN7 can only be used as inputs for the A/D
converter.
In the ACMCS versions these lines may also be used as digital inputs. In this case they are
addressed as an additional input port (port 6) via special function register P6 (0DB H ). Since port 6
has no internal latch, the contents of SFR P6 only depends on the levels applied to the input lines.
For details about this port please refer to section 7.1 (Parallel I/O).
Peripheral Control, Data and Status Registers
Most of the special function registers are used as control, status, and data registers to handle the
on-chip peripherals.
In the special function register table the register names are organized in groups and each of these
groups refer to one peripheral unit. More details on how to program these registers are given in the
descriptions of the following peripheral units:
Unit
Ports
Serial Channel
Timer 0/1
A/D-Converter
Timer 2 with Comp/Capt/Reload
Power Saving Modes
Watchdog Timer
Interrupt System
Semiconductor Group
*
Symbol
Section
–
7.1
–
7.2
–
7.3
ADC
7.4
CCU
7.5
–
7.6
WDT
7.7
–
8
26
Memory Organization
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