87C575 Philips Semiconductors, 87C575 Datasheet - Page 23

• Manufacturer Part Number: 87C575
• Description: 80C51 8-bit microcontroller family 8K/256 OTP/ROM/ROMless/ 4 comparator/ failure detect circuitry/ watchdog timer
• Manufacturer: Philips Semiconductors

Philips Semiconductors
Reduced EMI Mode
There are two bits in the AUXR register that
can be set to reduce the internal clock drive
and disable the ALE output. AO (AUXR.0)
when set turns off the ALE output. LO
(AUXR.1) when set reduces the drive of the
internal clock circuitry. Both bits are cleared
on Reset. With LO set the 87C575 will still
operate at 12MHz, but will have reduced EMI
in the range above 100MHz.
AUXR (8EH)
AO:
LO:
1998 May 01
––
80C51 8-bit microcontroller family
8K/256 OTP/ROM/ROMless, 4 comparator, failure detect circuitry, watchdog timer
* : WILL DISABLE PULLUPS
ON RELEVANT PINS
P1.0 / CMP0+
P1.1 / CMP0–
P3.5 / CMP1+
P3.6 / CMP2+
P3.7 / CMP3+
P3.4 / CMPR–
––
Turns off ALE output.
Reduces drive of internal clock
circuitry. 8XC575 spec’d to 12MHz
when LO set.
––
––
––
––
ENABLE
ENABLE
ENABLE
ENABLE
+
+
–
+
–
–
+
–
LO
EC3DP *
EC3TDC
AO
EC2DP *
EC2TDC
INTERNAL RESET
Internal resets generated by the power on,
low voltage, and oscillator fail detect circuits
are self timed to guarantee proper
initialization of the 8XC575. Reset will be held
approximately 24 oscillator periods after
normal conditions are detected by all enabled
detect circuits. Internal resets do not drive
RST but will cause missing pulses on ALE.
Interrupt Enable (IE) Register
EA
EC
ET2
ES
ET1
EX1
ET0
EX0
Figure 21. Analog Comparators
IE.7
IE.6
IE.5
IE.4
IE.3
IE.2
IE.1
IE.0
EC1DP *
EC1TDC
enable all interrupts
enable PCA interrupt
enable Timer 2 interrupt
enable Serial I/O interrupt
enable Timer 1 interrupt
enable External interrupt 1
enable Timer 0 interrupt
enable External interrupt 0
EC0DP *
TO CEX0 INPUT OF
TO CEX1 INPUT OF
TO CEX2 INPUT OF
TO CEX3 INPUT OF
PCA MODULE 0
PCA MODULE 1
PCA MODULE 2
PCA MODULE 3
23
EC0TDC
C3R0
EC3OD *
C2R0
EC2OD *
Interrupt Priority (IP) Register
PPC IP.6
PT2
PS
PT1
PX1
PT0
PX0
Priority Source
87C575
80C575/83C575/87C575
Power Control (PCON) Register
SMOD1 PCON.7 double baud rate bit
SMOD0 PCON.6 SCON.7 access control
OSF
POF
LVF
GF0
PD
IDL
Port 2 Pullup Disable Register
1
2
3
4
5
6
7
5
6
7
C1R0
IP.7
IP.5
IP.4
IP.3
IP.2
IP.1
IP.0
INT0
Timer 0
INT1
Timer 1
PCA
Serial I/O RI,TI
Timer 2
Serial I/O RI/TI
Timer 2
PCA
EC1OD *
PCON.5 oscillator fail flag
PCON.4 power off flag
PCON.3 low voltage flag
PCON.2 general purpose flag
PCON.1 power down mode bit
PCON.0 idle mode bit
80C575/83C575/
reserved
PCA interrupt priority
Timer 2 interrupt priority
Serial I/O interrupt priority
Timer 1 interrupt priority
External interrupt 1 priority
Timer 0 interrupt priority
External interrupt 0 priority
Flag
IE0
TF0
IE1
TF1
CF,CCFn 33H
TF2/EXF2 2BH lowest priority
TF2/EXF2 23H
CF, CCF
C0R0
EC0OD *
n
Product specification
Vector
03H highest priority
0BH
13H
1BH
23H
23H
33H lowest priority
P1.3 / CMP0
P1.4 / CMP1
P1.5 / CMP2
P1.6 / CMP3
87C575
(E8H)
CMP
CMPE
(91H)
SU00244