1999 Mar 12
4
Philips Semiconductors
Product specification
8-bit microcontroller
P8xC557E8
2.1
Electromagnetic Compatibility (EMC)
Primary attention is paid to the reduction of
electromagnetic emission of the microcontroller
P8xC557E8. The following features reduce the
electromagnetic emission and additionally improve the
electromagnetic susceptibility:
Four digital part supply voltage pins (V
DD1
to V
DD4
) and
four digital ground pins (V
SS1
to V
SS4
) are placed as
pairs of V
DDn
and V
SSn
at two adjacent pins, at each side
of the package.
Separated V
DD
pins for the internal logic and the port
buffers.
Internal decoupling capacitance improves the EMC
radiation behaviour and the EMC immunity.
External capacitors should be connected across
associated V
DDn
and V
SSn
pins (i.e. V
DD1
and V
SS1
).
Lead length should be as short as possible. Ceramic
chip capacitors are recommended (100 nF).
2.2
Recommendation on ALE
For applications that require no external memory or
temporarily no external memory: the ALE output signal
(pulses at a frequency of
1
6
×
f
OSC
) can be disabled under
software control (bit RFI; SFR: PCON.5); if disabled, no
ALE pulse will occur. ALE pin will be pulled down
internally, switching an external address latch to a quiet
state. The MOVX instruction will still toggle ALE (external
Data Memory is accessed). ALE will retain its normal HIGH
value during Idle mode and a LOW value during
Power-down mode while in the ‘
RFI
reduction mode’.
Additionally during internal access (EA = 1) ALE will toggle
normally when the address exceeds the internal Program
Memory size. During external access (EA = 0) ALE will
always toggle normally, whether the flag ‘RFI’ is set or not.
3
ORDERING INFORMATION
Notes
1.
2.
3.
ROMless type.
ROM coded type; ‘nnn’ denotes the ROM code number.
EPROM/OTP type.
TYPE NUMBER
PACKAGE
FREQUENCY
RANGE (MHZ)
TEMPERATURE
RANGE (
°
C)
NAME
DESCRIPTION
VERSION
P80C557E8EFB
(1)
P83C557E8EFB/nnn
(2)
P87C557E8EFB
(3)
QFP80
plastic quad flat package;
80 leads (lead length 1.95 mm);
body 14
×
20
×
2.8 mm
SOT318-2
3.5 to 16
40 to +85