R8C/13 Group
12.3 Timer (Timer Z)
12.3.1 Timer Mode
In this mode, the timer counts an internally generated count source or Timer Y underflow (see “Table
12.9 Timer Mode Specifications”). The TZSC register is unused in timer mode. Figure 12.22 shows
the TYZMR register and PUM register in timer mode.
Table 12.9 Timer Mode Specifications
Item
Count source
Count operation
Specification
f1, f2, f8, Timer Y underflow
• Down-count
• When the timer underflows, it reloads the reload register contents before continuing
counting (When the Timer Z underflows, the contents of the Timer Z primary reload
register is reloaded.)
Divide ratio
1/(n+1)(m+1)
n: set value in PREZ register, m: set value in TZPR register
Count start condition
Count stop condition
Interrupt request
generation timing
Write “1” (count start) to TZS bit in TYZMR register
Write “0” (count stop) to TZS bit in TYZMR register
• When Timer Z underflows [Timer Z interrupt]
TZOUT pin function
Programmable I/O port
_______
INT0 pin function
Read from timer
Programmable I/O port, or I_N__T__0_ interrupt input
Count value can be read out by reading TZPR register.
Same applies to PREZ register.
Write to timer(1)
Value written to TZPR register is written to both reload register and counter or written to
reload register only. Selected by program.
Same applies to PREZ register.
NOTES:
1. The IR bit in the TZIC register is set to "1" (interrupt requested) if you write to the TZPR or PREZ register while both
of the following conditions are met.
<Conditions>
• TZWC bit in TYZMR register is set to "0" (write to reload register and counter simultaneously)
• TZS bit in TYZMR register is set to "1" (count start)
To write to the TZPR or PREZ register in the above state, disable interrupts before the writing.
Rev.1.20 Jan 27, 2006 page 91 of 205
REJ09B0111-0120
RENESAS [ RENESAS TECHNOLOGY CORP ]
