R8C-12_1 Datasheet, PDF (78/198 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / R8C /Tiny SERIES

R8C/12 Group
12.2 Timer (Timer Y)
12.2.1 Timer Mode
In this mode, the timer counts an internally generated count source (see “Table 12.7 Timer Mode
Specifications”). An external signal input to the CNTR1 pin can be counted. The TYSC register is
unused in timer mode. Figure 12.15 shows the TYZMR and PUM registers in timer mode.
Table 12.7 Timer Mode Specifications
Item
Specification
Count source
f1, f8, fRING, external signal fed to CNTR1 pin
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.)
Divide ratio
1/(n+1)(m+1) n: set value in PREY register, m: set value in TYPR register
Count start condition
Write “1” (count start) to TYS bit in TYZMR register
Count stop condition
Write “0” (count stop) to TYS bit in TYZMR register
Interrupt request
• When Timer Y underflows [Timer Y interrupt]
generation timing
________
INT2/CNTR1 pin function
_______
Programmable I/O port, count source input or INT2 interrupt input
• When the TYCK1 to TYCK0 bits in the TCSS register are set to “00b”, “01b” or “10b”
_______
(Timer Y count source is f1, f8 or fRING), programmable I/O port or INT2 interrupt input
• When the TYCK1 to TYCK0 bits are set to “11b” (Timer Y count source is CNTR1
_______
input), count source input (INT2 interrupt input)
Read from timer
Count value can be read out by reading TYPR register.
Write to timer⁽¹⁾
Same applies to PREY register.
Value written to TYPR register is written to both reload register and counter or written to
only reload register. Selected by program.
Same applies to PREY register.
Select function
• Event counter function
When setting TYCK1 to TYCK0 bits to “112”, an external signal fed to CNTR1 pin is
counted.
_______
• INT2/CNTR1 switching bit
Active edge of count source is selected by R1EDG bit.
NOTES:
1. The IR bit in the TYIC register is set to "1" (interrupt requested) if you write to the TYPR or PREY register while both
of the following conditions are met.
Conditions:
• TYWC bit in TYZMR register is "0" (write to reload register and counter simultaneously)
• TYS bit is "1" (count start)
To write to the TYPR or PREY register in the above state, disable interrupts before writing.
Rev.1.20 Jan 27, 2006 page 68 of 181
REJ09B0110-0120