DS87C530 Maxim, DS87C530 Datasheet - Page 21

• Manufacturer Part Number: DS87C530
• Description: The DS87C530/DS83C530 EPROM/ROM microcontrollers with a real-time clock (RTC) are 8051-compatible microcontrollers based on the Dallas Semiconductor high-speed core
• Manufacturer: Maxim

Table 6. PMM Control and Status Bit Summary
CD1, CD0
XT/ RG
XTOFF
NAME
RGMD
SPRA1
SPRA0
SPTA1
SPTA0
XTUP
SWB
HIP
LIP
PIP
PMR7, PMR.6
LOCATION
STATUS.7
STATUS.6
STATUS.5
STATUS.4
STATUS.3
STATUS.2
STATUS.1
STATUS.0
EXIF.3
EXIF.2
PMR.5
PMR.3
Control. XT/ RG =1, runs from crystal or external
clock; XT/ RG =0, runs from internal ring oscillator.
Status. RGMD=1, CPU clock = ring; RGMD = 0,
CPU clock = crystal.
Control. CD1, 0 = 01, 4 clocks; CS1, 0 = 10, PMM1;
CD1, 0 = 11, PMM2.
Control. SWB = 1, hardware invokes switchback to 4
clocks, SWB = 0, no hardware switchback.
Control. Disables crystal operation after ring is
selected.
Status. 1 indicates a power-fail interrupt in service.
Status. 1 indicates high priority interrupt in service.
Status. 1 indicates low priority interrupt in service.
Status. 1 indicates that the crystal has stabilized.
Status. Serial transmission on serial port 1.
Status. Serial word reception on serial port 1.
Status. Serial transmission on serial port 0.
Status. Serial word reception on serial port 0.
DS87C530/DS83C530 EPROM/ROM Microcontrollers with Real-Time Clock
FUNCTION
21 of 45
RESET
0, 1
X
0
0
0
0
0
0
1
0
0
0
0
0 to 1 only when
XTUP = 1 and
XTOFF= 0
None
Write CD1, 0 = 10 or
11 only from CD1, 0 =
01
Unrestricted
1 only when XT/ RG
= 0
None
None
None
None
None
None
None
None
WRITE ACCESS