P89C738ABB Просмотр технического описания (PDF) - Philips Electronics
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P89C738ABB Datasheet PDF : 64 Pages
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Philips Semiconductors
8-bit Flash microcontrollers
han6db4okobk,yftuellspagewidth
64 kbytes
Product specification
P89C738; P89C739
64 kbytes
INTERNAL
(EA = 1)
EXTERNAL
(EA = 0)
0
PROGRAM MEMORY
OVERLAPPED SPACE
255
INDIRECT ONLY
127
DIRECT AND
INDIRECT
0
MAIN RAM
SFRs
256
AUXILIARY
RAM
INTERNAL DATA MEMORY
MBK524
EXTERNAL
DATA MEMORY
Fig.9 Internal and external data memory address space.
8.3 Addressing
The P89C738 has five modes for addressing:
• 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 addresses is as follows:
• Register in one of the four 8-bit register banks through
Register, Direct or Register-Indirect addressing
• 512 bytes of internal RAM through Direct or
Register-Indirect addressing. 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 indirectly
as data RAM. Bytes 0 to 255 of AUX-RAM can only be
addressed indirectly via MOVX.
• SFR through Direct addressing at address locations
128 to 255
• External data memory through Register-Indirect
addressing
• Program memory look-up tables through Base-Register
plus Index-Register-Indirect addressing.
1998 Apr 07
16
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