hd64338342hw Renesas Electronics Corporation., hd64338342hw Datasheet - Page 363

• Manufacturer Part Number: hd64338342hw
• Description: Renesas 8-bit Single-chip Microcomputer H8 Family/h8/300l Super Low Power Series
• Manufacturer: Renesas Electronics Corporation.

Bit 3: Asynchronous event counter module standby mode control (AECKSTP)
Bit 3 controls setting and clearing of module standby mode for the asynchronous event counter.
AECKSTP
0
1
9.7.3
1. 16-bit Event Counter Operation
When bit CH2 is cleared to 0 in ECCSR, ECH and ECL, operate as a 16-bit event counter. Figure
9.20 shows an example of the software processing when ECH and ECL are used as a 16-bit event
counter.
As CH2 is cleared to 0 by a reset, ECH and ECL operate as a 16-bit event counter after a reset.
They can also be used as a 16-bit event counter by carrying out the software processing shown in
the example in figure 9.20. The operating clock source is asynchronous event input from the
AEVL pin. When the next clock is input after the count value reaches H'FF in both ECH and
ECL, ECH and ECL overflow from H'FFFF to H'0000, the OVH flag is set to 1 in ECCSR, the
ECH and ECL count values each return to H'00, and counting up is restarted. When overflow
Figure 9.20 Example of Software Processing when Using ECH and ECL as 16-Bit Event
Operation
Asynchronous event counter is set to module standby mode
Asynchronous event counter module standby mode is cleared
Description
Clear CH2 to 0
Clear CUEH, CUEL, CRCH, and CRCL to 0
Clear OVH and OVL to 0
Set CUEH, CUEL, CRCH, and CRCL to 1
Counter
Start
End
Rev. 6.00 Aug 04, 2006 page 327 of 680
REJ09B0145-0600
Section 9 Timers
(initial value)