1998 Oct 07
12
Philips Semiconductors
Product specification
Pager baseband controller
PCA5007
6.5
Addressing
The PCA5007 has five methods for addressing source
operands:
Register
Direct
Register-Indirect
Immediate
Base-Register plus Index-Register-Indirect.
The first three methods can be used for addressing
destination operands. Most instructions have a
‘destination/source’ field that specifies the data type,
addressing methods and operands involved. For
operations other than MOVs, the destination operand is
also a source operand.
Access to memory addressing is as follows:
Registers in one of the four 8-register banks through
Register-Direct or Register-Indirect
Maximum 1024 bytes of internal data RAM through
Direct or Register-Indirect
– Bytes 0 to 127 of internal RAM may be addressed
directly/indirectly. Bytes 128 to 255 of internal RAM
share their address location with the SFRs and so
may only be addressed Register-Indirect as data
RAM.
– Bytes 0 to 768 of AUX-RAM can only be addressed
indirectly via MOVX. Bytes 256 to 768 can only be
addressed using indirect addressing with the data
pointer, while bytes 0 to 255 may be also addressed
using R0 or R1.
Special function registers through Direct
Program memory Look-Up Tables (LUTs) through
Base-Register plus Index-Register-Indirect.
The PCA5007 is classified as an 8-bit device since the
internal ROM, RAM, Special Function Registers (SFRs),
Arithmetic Logic Unit (ALU) and external data bus are all
8 bits wide. It performs operations on bit, nibble, byte and
double-byte data types.
Facilities are available for byte transfer, logic and integer
arithmetic operations. Data transfer, logic and conditional
branch operations can be performed directly on Boolean
variables to provide excellent bit handling.
While the PCA5007 is executing code from the internal
memory, ALE and PSEN pins are inactive with
ALE = LOW and PSEN = HIGH.
External XRAM is not supported for this device, since
P3.7 (RD) and P3.6 (WR) pins are not available. If the
external XRAM is accessed accidentally, no PSEN or ALE
cycle is done and actual P0 values are read. Internal
XRAM access is not visible from outside the chip (no ALE,
PSEN, P0 and P2 activity).