71M6531D_10 Datasheet, PDF (28/120 Pages) Teridian Semiconductor Corporation – Energy Meter IC

Data Sheet 71M6531D/F-71M6532D/F
FDS 6531/6532 005
Bit
S1CON[2]
S1CON[1]
S1CON[0]
Symbol
RB81
TI1
RI1
Function
In Modes A and B, it is the 9^th data bit received. In Mode B, if SM21 is 0,
RB81 is the stop bit. Must be cleared by software
Transmit interrupt flag, set by hardware after completion of a serial transfer.
Must be cleared by software.
Receive interrupt flag, set by hardware after completion of a serial reception.
Must be cleared by software.
Bit
PCON[7]
PCON[6:2]
PCON[1]
PCON[0]
Table 19: PCON Register Bit Description (SFR 0x87)
Symbol
Function
SMOD
The SMOD bit doubles the baud rate when set
–
Not used.
STOP
Stops MPU flash access and MPU peripherals including timers and
UARTs when set until an external interrupt is received.
IDLE
Stops MPU flash access when set until an internal interrupt is received.
1.4.7 Timers and Counters
The 80515 has two 16-bit timer/counter registers: Timer 0 and Timer 1. These registers can be configured
for counter or timer operations.
In timer mode, the register is incremented every 12 MPU clock cycles. In counter mode, the register is
incremented when the falling edge is observed at the corresponding input signal T0 or T1 (T0 and T1 are
the timer gating inputs derived from certain DIO pins, see Section 1.5.7 Digital I/O). Since it takes 2 machine
cycles to recognize a 1-to-0 event, the maximum input count rate is 1/2 of the clock frequency (CKMPU).
There are no restrictions on the duty cycle, however to ensure proper recognition of the 0 or 1 state, an
input should be stable for at least 1 machine cycle.
Four operating modes can be selected for Timer 0 and Timer 1, as shown in Table 20 and Table 21. The
TMOD Register, shown in Table 22, is used to select the appropriate mode. The timer/counter operation
is controlled by the TCON Register, which is shown in Table 23. Bits TR1 (TCON[6]) and TR0 (TCON[4]) in
the TCON register start their associated timers when set.
Table 20: Timers/Counters Mode Description
M1
M0
Mode
Function
13-bit Counter/Timer mode with 5 lower bits in the TL0 or TL1 register
0
0
Mode 0 and the remaining 8 bits in the TH0 or TH1 register (for Timer 0 and Timer
1, respectively). The 3 high order bits of TL0 and TL1 are held at zero.
0
1
Mode 1 16-bit Counter/Timer mode.
8-bit auto-reload Counter/Timer. The reload value is kept in TH0 or
1
0
Mode 2
TH1, while TL0 or TL1 is incremented every machine cycle. When TL(x)
overflows, a value from TH(x) is copied to TL(x) (where x = 0 for
counter/timer 0 or 1 for counter/timer 1.
If Timer 1 M1 and M0 bits are set to 1, Timer 1 stops.
1
1
Mode 3 If Timer 0 M1 and M0 bits are set to 1, Timer 0 acts as two independent
8-bit Timer/Counters.
In Mode 3, TL0 is affected by TR0 and gate control bits and sets the TF0 flag on overflow, while TH0
is affected by the TR1 bit and the TF1 flag is set on overflow.
Table 21 specifies the combinations of operation modes allowed for Timer 0 and Timer 1.
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