4513_03 Datasheet, PDF (47/210 Pages) Renesas Technology Corp – 4-BIT SINGLE-CHIP MICROCOMPUTER

HARDWARE
FUNCTION BLOCK OPERATIONS
(6) Timer 3 (interrupt function)
Timer 3 is an 8-bit binary down counter with the timer 3 reload reg-
ister (R3). Data can be set simultaneously in timer 3 and the reload
register (R3) with the T3AB instruction. Data can be written to re-
load register (R3) with the TR3AB instruction.
When writing data to reload register R3 with the TR3AB instruction,
the downcount after the underflow is started from the setting value
of reload register R3.
Timer 3 starts counting after the following process;
Πset data in timer 3,
 select the count source with the bits 0 and 1 of register W3, and
Ž set the bit 3 of register W3 to “1.”
However, P31/INT1 pin input can be used as the star t trigger for
timer 3 count operation by setting the bit 2 of register W3 to “1.”
When a value set in timer 3 is n, timer 3 divides the count source
signal by n + 1 (n = 0 to 255).
Once count is started, when timer 3 underflows (the next count
pulse is input after the contents of timer 3 becomes “0”), the timer
3 interrupt request flag (T3F) is set to “1,” new data is loaded from
reload register R3, and count continues (auto-reload function).
Data can be read from timer 3 with the TAB3 instruction. When
reading the data, stop the counter and then execute the TAB3 in-
struction. Timer 3 underflow signal divided by 2 can be output from
D7/CNTR1 pin.
(7) Timer 4 (interrupt function)
Timer 4 is an 8-bit binary down counter with the timer 4 reload reg-
ister (R4). Data can be set simultaneously in timer 4 and the reload
register (R4) with the T4AB instruction.
Timer 4 starts counting after the following process;
Πset data in timer 4,
 select the count source with the bits 0 and 1 of register W4, and
Ž set the bit 3 of register W4 to “1.”
When a value set in timer 4 is n, timer 4 divides the count source
signal by n + 1 (n = 0 to 255).
Once count is started, when timer 4 underflows (the next count
pulse is input after the contents of timer 4 becomes “0”), the timer
4 interrupt request flag (T4F) is set to “1,” new data is loaded from
reload register R4, and count continues (auto-reload function).
Data can be read from timer 4 with the TAB4 instruction. When
reading the data, stop the counter and then execute the TAB4 in-
struction. The output from D7/CNTR1 pin by timer 4 underflow
signal divided by 2 can be controlled.
(8) Timer interrupt request flags (T1F, T2F,
T3F, and T4F)
Each timer interrupt request flag is set to “1” when each timer
underflows. The state of these flags can be examined with the skip
instructions (SNZT1, SNZT2, SNZT3, and SNZT4).
Use the interrupt control registers V1, V2 to select an interrupt or a
skip instruction.
An interrupt request flag is cleared to “0” when an interrupt occurs
or when the next instruction is skipped with a skip instruction.
(9) Timer I/O pin (D6/CNTR0, D7/CNTR1)
D6/CNTR0 pin has functions to input the timer 2 count source, and
to output the timer 1 and timer 2 underflow signals divided by 2. D7/
CNTR1 pin has functions to input the timer 4 count source, and to
output the timer 3 and timer 4 underflow signals divided by 2.
The selection of D6/CNTR0 pin function can be controlled with the
bit 0 of register W6. The selection of D7/CNTR1 pin function can be
controlled with the bit 2 of register W6.
The following signals can be selected for the CNTR0 output signal
with the bit 1 of register W6.
• timer 1 underflow signal divided by 2
• the signal of AND operation between timer 1 underflow signal di-
vided by 2 and timer 2 underflow signal divide by 2
The following signals can be selected for the CNTR1 output signal
with the bit 3 of register W6.
• timer 3 underflow signal divided by 2
• the signal of AND operation between timer 3 underflow signal di-
vided by 2 and timer 4 underflow signal divide by 2
Timer 2 counts the rising waveform of CNTR0 input when the
CNTR0 input is selected as the count source.
Timer 4 counts the rising waveform of CNTR1 input when the
CNTR1 input is selected as the count source.
(10) Count start synchronous circuit (timer 1
and 3)
Each of timer 1 and timer 3 has the count start synchronous circuit
which synchronizes P30/INT0 pin and P31/INT1 pin, respectively,
and can start the timer count operation.
Timer 1 count start synchronous circuit function is selected by set-
ting the bit 0 of register W1 to “1.” The control by P30/INT0 pin input
can be performed by setting the bit 0 of register I1 to “1.”
The count start synchronous circuit is set by level change (“H”→“L”
or “L”→“H”) of P30/INT0 pin input. This valid waveform is selected
by bits 1 (I11) and 2 (I12) of register I1 as follows;
• I11 = “0”: Synchronized with one-sided edge (falling or rising)
• I11 = “1”: Synchronized with both edges (both falling and rising)
When register I11=“0” (synchronized with the one-sided edge), the ris-
ing or falling waveform can be selected by bit 2 of register I1;
• I12 = “0”: Falling waveform
• I12 = “1”: Rising waveform
Timer 3 count start synchronous circuit function is selected by set-
ting the bit 2 of register W3 to “1.” The control by P31/INT1 pin input
can be performed by setting the bit 0 of register I2 to “1.”
The count start synchronous circuit is set by level change (“H”→“L”
or “L”→“H”) of P31/INT1 pin input. This valid waveform is selected
by bits 1 (I21) and 2 (I22) of register I2 as follows;
• I21 = “0”: Synchronized with one-sided edge (falling or rising)
• I21 = “1”: Synchronized with both edges (both falling and rising)
When register I21=“0” (synchronized with the one-sided edge), the ris-
ing or falling waveform can be selected by bit 2 of register I2;
• I22 = “0”: Falling waveform
• I22 = “1”: Rising waveform
When timer 1 and timer 3 count start synchronous circuits are
used, the count start synchronous circuits are set, the count source
is input to each timer by inputting valid waveform to P30/INT0 pin
and P31/INT1 pin. Once set, the count start synchronous circuit is
cleared by clearing the bit I10 or I20 to “0” or reset.
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4513/4514 Group User’s Manual