
CHAPTER 9 8-BIT TIMER/EVENT COUNTER 5
Preliminary User’s Manual U16895EJ1V0UD
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9.4.6 Operation as external event counter (16 bits)
The 16-bit resolution timer/event counter mode is selected by setting the TMC51.TMC514 bit to 1.
The external event counter counts the number of clock pulses input to the TI50 pin from an external source using
16-bit timer counter 5 (TM5).
Setting method
<1>
Set each register.
TCL50 register:
Selects the TI50 pin input edge.
(The TCL51 register does not have to be set during cascade connection.)
Falling edge of TI50 pin
→ TCL50 register = 00H
Rising edge of TI50 pin
→ TCL50 register = 01H
CR50 register:
Compare value (N) ... Lower 8 bits (settable from 00H to FFH)
CR51 register:
Compare value (N) ... Higher 8 bits (settable from 00H to FFH)
TMC50, TMC51 registers: Stops count operation, selects the clear & start mode entered on a match
between the TM5 register and CR5 register, disables timer output F/F
inversion, and disables timer output.
(
×: don’t care)
TMC50 register = 0000xx00B
TMC51 register = 0001xx00B
For the alternate-function pin settings, refer to Table 4-14 Settings When Port Pins Are Used for
Alternate Functions.
<2>
Set the TMC51.TCE51 bit to 1. Then set the TMC50.TCE50 bit to 1 and count the number of pulses input
from the TI50 pin.
<3>
When the values of the TM5 register and CR5 register connected in cascade match, the INTTM50 signal
is generated (the TM5 register is cleared to 0000H).
<4>
The INTTM50 signal is then generated each time the values of the TM5 register and CR5 register match.
INTTM50 signal is generated when the valid edge is input to the TI50 pin N + 1 times: N = 0000H to FFFFH
Cautions 1. During external event counter operation, do not rewrite the value of the CR5n
register.
2. To write using 8-bit access during cascade connection, set the TCE51 bit to 1 and
then set the TCE50 bit to 1. When operation is stopped, clear the TCE50 bit to 0 and
then clear the TCE51 bit to 0 (n = 0, 1).
3. During cascade connection, TI50 pin input and the INTTM50 signal are used. Do not
use TI51 pin input, TO51 pin output, and the INTTM51 signal; mask them instead (for
details, refer to CHAPTER 19
INTERRUPT/EXCEPTION PROCESSING FUNCTION).
Clear the LVS51, LVR51, TMC511, and TOE51 bits to 0.
4. Do not change the value of the CR5 register during external event counter operation.