Datasheet

C515C

Data Sheet 21 2003-02

Figure 7 Recommended Oscillator Circuitries

Multiple Datapointers

As a functional enhancement to the standard 8051 architecture, the C515C contains

eight 16-bit datapointers instead of only one datapointer. The instruction set uses just

one of these datapointers at a time. The selection of the actual datapointer is done in the

special function register DPSEL. Figure 8 illustrates the datapointer addressing

mechanism.

Figure 8 External Data Memory Addressing using Multiple Datapointers

MCT02765

XTAL1

XTAL2 XTAL2

XTAL1

Crystal/Resonator Oscillator Mode Driving from External Source

External Oscillator

Signal

N.C.

2 - 10 MHz

C = 20 pF ± 10 pF (incl. stray capacitance)

Crystal Mode :

:Resonator Mode

= depends on selected ceramic resonatorC

DPH(83 ) DPL(82 )

DPTR0

DPTR7

.0.1.2-----

DPSEL(92 )

DPSEL Selected

Data-

pointer

.2 .1 .0

DPTR 0000

0 0 1 DPTR 1

0 1 0 DPTR 2

0 1 1 DPTR 3

1 0 0 DPTR 4

1 0 1 DPTR 5

1 1 0 DPTR 6

1 1 1 DPTR 7

MCD00779

External Data Memory