W741L250 Datasheet, PDF (12/86 Pages) Winbond – 4-BIT MICROCONTROLLER

W741L250
Mode Register 0 (MR0)
Mode Register 0 is organized as a 4-bit binary register (MR0.0 to MR0.3). MR0 can be used to control
the operation of Timer 0. The bit descriptions are as follows:
3210
MR0 W
W
Note: W means write only.
Bit 0 = 0 The internal fundamental frequency of Timer 0 is FOSC/4.
= 1 The internal fundamental frequency of Timer 0 is FOSC/1024.
Bit 1
Reserved
Bit 2
Reserved
Bit 3 = 0 Timer 0 stops down-counting.
= 1 Timer 0 starts down-counting.
Mode Register 1 (MR1)
Mode Register 1 is organized as a 4-bit binary register (MR1.0 to MR1.3). MR1 can be used to control
the operation of Timer 1. The bit descriptions are as follows:
3210
MR1 W W W W
Note: W means write only.
Bit 0 = 0 The internal fundamental frequency of Timer 1 is FOSC.
= 1 The internal fundamental frequency of Timer 1 is FOSC/64.
Bit 1 = 0 The fundamental frequency source of Timer 1 is the internal clock.
= 1 The fundamental frequency source of Timer 1 is the external clock from RC.0 input pin.
Bit 2 = 0 The specified waveform of the MFP generator is delivered at the MFP output pin.
= 1 The specified frequency of Timer 1 is delivered at the MFP output pin.
Bit 3 = 0 Timer 1 stops down-counting.
= 1 Timer 1 starts down-counting.
Interrupts
The W741L250 provides three internal interrupt sources (Divider 0, Timer 0, Timer 1) and two
external interrupt sources ( INT , port RC). Vector addresses for each of the interrupts are located in
the range of program memory (ROM) addresses 004H to 020H. The flags IEF, PEF, and EVF are
used to control the interrupts. When EVF is set to "1" by hardware and the corresponding bits of IEF
and PEF have been set by software, an interrupt is generated. When an interrupt occurs, all of the
interrupts are inhibited until the EN INT or MOV IEF, #I instruction is invoked. The interrupts can also
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