71M6543F Datasheet, PDF (43/157 Pages) Maxim Integrated Products – Selectable Gain of 1 or 8 for One Current Energy Meter ICs Metrology Compensation

71M6543F/H and 71M6543G/GH Data Sheet
SFR enable bits must be set to permit any of these interrupts to occur. Likewise, each interrupt has its own
flag bit, which is set by the interrupt hardware, and reset by the MPU interrupt handler. XFER_BUSY,
RTC_1SEC, RTC_1MIN, RTC_T, SPI, PLLRISE and PLLFALL have their own enable and flag bits in
addition to the interrupt 6, 4 and enable and flag bits (see Table 33: Interrupt Enable and Flag Bits).
IE0 through IEX6 are cleared automatically when the hardware vectors to the interrupt handler.
The other flags, IE_XFER through IE_VPULSE, are cleared by writing a zero to them.
Since these bits are in an SFR bit addressable byte, common practice would be to clear them
with a bit operation, but this must be avoided. The hardware implements bit operations as a
byte wide read-modify-write hardware macro. If an interrupt occurs after the read, but before
the write, its flag is cleared unintentionally.
The proper way to clear the flag bits is to write a byte mask consisting of all ones except for a
zero in the location of the bit to be cleared. The flag bits are configured in hardware to ignore
ones written to them.
Table 33: Interrupt Enable and Flag Bits
Interrupt Enable
Name
Location
Interrupt Flag
Name
Location
Interrupt Description
EX0
EX1
EX2
EX3
EX4
EX5
EX6
EX_XFER
EX_RTC1S
EX_RTC1M
EX_RTCT
EX_SPI
EX_EEX
EX_XPULSE
EX_YPULSE
EX_WPULSE
EX_VPULSE
SFR A8[[0]
SFR A8[2]
SFR B8[1]
SFR B8[2]
SFR B8[3]
SFR B8[4]
SFR B8[5]
2700[0]
2700[1]
2700[2]
2700[4]
2701[7]
2700[7]
2700[6]
2700[5]
2701[6]
2701[5]
IE0
IE1
IEX2
IEX3
IEX4
IEX5
IEX6
IE_XFER
IE_RTC1S
IE_RTC1M
IE_RTCT
IE_SPI
IE_EEX
IE_XPULSE
IE_YPULSE
IE_WPULSE
IE_VPULSE
SFR 88[1]
SFR 88[3]
SFR C0[1]
SFR C0[2]
SFR C0[3]
SFR C0[4]
SFR C0[5]
SFR E8[0]
SFR E8[1]
SFR E8[2]
SFR E8[4]
SFR F8[7]
SFR E8[7]
SFR E8[6]
SFR E8[5]
SFR F8[4]
SFR F8[3]
External interrupt 0
External interrupt 1
External interrupt 2
External interrupt 3
External interrupt 4
External interrupt 5
External interrupt 6
XFER_BUSY interrupt (int 6)
RTC_1SEC interrupt (int 6)
RTC_1MIN interrupt (int 6)
RTC_T interrupt (int 6)
SPI interrupt
EEPROM interrupt
CE_Xpulse interrupt (int 2)
CE_Ypulse interrupt (int 2)
CE_Wpulse interrupt (int 2)
CE_Vpulse interrupt (int 2)
Interrupt Priority Level Structure
All interrupt sources are combined in groups, as shown in Table 34.
Group
0
1
2
3
4
5
Table 34: Interrupt Priority Level Groups
Group Members
External interrupt 0
Timer 0 interrupt
External interrupt 1
Timer 1 interrupt
Serial channel 0 interrupt
–
Serial channel 1 interrupt
–
–
External interrupt 2
–
External interrupt 3
–
External interrupt 4
–
External interrupt 5
–
External interrupt 6
Each group of interrupt sources can be programmed individually to one of four priority levels (as shown in
Table 35) by setting or clearing one bit in the SFR interrupt priority register IP0 (SFR 0xA9) and one in
v1.2
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