1996 Jun 27
73
Philips Semiconductors
Product specication
8-bit microcontroller with on-chip CAN
P8xCE598
17.1
Power-on Reset
If the RST pin is connected to VDD via a 2.2 F capacitor,
as shown in Fig.26, an automatic reset can be obtained by
switching on VDD (provided its rise time is <10 ms). The
decrease of the RST pin voltage depends on the capacitor
and the internal resistor RRST. That voltage must remain
above the lower threshold for at minimum the oscillator
start-up time plus 2 machine cycles.
18 INSTRUCTION SET
The P8xCE598 uses the powerful instruction set of the
P80C51. It consists of 49 single-byte, 45 two-byte and 17
three-byte instructions. Using a 16 MHz quartz, 64 of the
instructions are executed in 0.75
s, 45 in 1.5 s and the
multiply, divide instructions in 3
s. A summary of the
instruction set is given in Tables 84, 85, 86, 87 and 88.
Fig.26 Power-on-reset.
handbook, halfpage
V
DD
V
DD
RST
2.2
F
R RST
MLB232
P8xCE598
18.1
Addressing Modes
Most instructions have a ‘destination/source’ field that
specifies the data type, addressing modes and operands
involved. For all these instructions, except from MOVs, the
destination operand is also a source operand
(e.g. ADD A, R7).
Five types of addressing modes are used:
Register Addressing,
– R0 to R7 (4 banks)
– A,B,C (bit), AB (2 bytes), DPTR (double byte).
Direct Addressing,
– lower 128 bytes of internal Main RAM
(including the 4 R0 to R7 register banks)
– Special Function Registers (SFRs)
– 128 bits in a subset of the internal Main RAM
(see Fig.5)
– 128 bits in a subset of the Special Function Registers
(see Figs 6 and 7).
Register-Indirect Addressing,
– internal RAM (@R0, @R1, @SP
[PUSH/POP])
– internal Auxiliary RAM (@R0, @R1, @DPTR)
– external Data Memory (@DPTR).
Immediate Addressing,
– Program Memory (in-code 8 bit or 16 bit constant)
Base-Register-plus Index-Register-Indirect Addressing,
– Program Memory look-up table
(@DPTR+A, @PC+A).
The first three addressing modes are usable for
destination operands.