
Under
development
Tentative Specifications REV.E
Specifications in this manual are tentative and subject to change.
Mitsubishi microcomputers
M30100/M30102 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Timer Y
74
(1) Timer mode
In this mode, the timer counts an internally generated count source. (See Table 1.14.8) The Timer Y
secondary is unused in this mode. Figure 1.14.17 shows the Timer Y, Z mode register and Timer Y, Z
waveform output control register in timer mode.
Item
Specification
Count source
f1, f8, ring oscillator output, fC32
Count operation
Down count
When the timer underflows, it reloads the reload register contents before continuing
counting (When the Timer Y underflows, the contents of the Timer Y primary reload
register is reloaded.)
When a counting stops, the timer reloads the content of the reload register before it
stops.
Divide ratio
1/(n+1)/(m+1) n : Set value of Prescaler Y, m: Set value of Timer Y primary
Count start condition
Count start flag is set (=1)
Count stop condition
Count start flag is reset (=0) (Note 1)
Interrupt request generation timing When Timer Y underflows
TYOUT pin function
Programmable I/O port
Read from timer
Count value can be read out by reading Timer Y primary register.
Same applies to Prescaler Y register.
Write to timer
When a value is written to Timer Y Primary register, it is written to both reload register
and counter or written to only reload register. Selected by software.
Same applies to Prescaler Y register.
Select function
Timer Y write control function
When a value is written to Timer Y Primary register, it can be selected that the value is
written to both reload register and counter or written to only reload register.
Same applies to Prescaler Z register. (Note 2)
Note 1: When the count is stopped, the Timer Y interrupt request flag becomes "1" and an interrupt may occur. Thus,
interrupts must be disabled before the count is stopped. Furthermore, set the Timer Y interrupt request flag to "0"
before starting counting again.
Note 2: If writing to the Timer Y or prescaler Y under the following conditions being filled at the same time the Timer Y
interrupt request flag becomes "1" and an interrupt occurs.
<Conditions>
Timer Y write control bit (bit 2 of address 0080) is "0" (write to timer and reload register simultaneously)
Timer Y count start flag (bit 3 of address 0080) is "1" (count start)
To write to the Timer Y or prescaler Y in the above state, disable interrupts before writing.
Table 1.14.8. Specifications of timer mode