M37517F8HP Datasheet, PDF (42/98 Pages) Renesas Technology Corp – SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER

7517 Group
Notes on current integrator
When changing current integration into prohibition from permis-
sion, incorrect interrupt may occur. Perform any one of the
following by software as the measure.
(1) How to control timing which disable current integrator
•When changing current integration to prohibition in the current in-
tegrate mode, change the setting during “H” of the clock signal
which operates in a cycle of 125 ms.
•When changing current integration to prohibition in the calibration
mode, change the setting during “H” of the clock signal operated
by cycle which is set by the calibration period selection bits.
Table 10 shows the how to distinguish “H” period of each clock
signal.
(2) How to invalidate interrupt after prohibition setup of current in-
tegrator
After changing current integration to prohibition, wait for about
61.0 ms, and then set the request flag to “0”.
(3) How to check truth of interrupt request
•Check the current integrate enable bit during the current integra-
tor interrupt routine. When disabling the current integrator, skip
the interrupt processing.
Notes on AD conversion connection mode
•When the AD conversion of the current integrator is performed,
do not execute other AD conversion.
•When using the AD conversion connection mode at the time of
calibration completion, do not set the AD conversion connection
bit to “1” before calibration starts.
•The count value immediately after AD conversion completion of
the current integrator may be incorrect. Only when the count
value immediately after the AD conversion completion, such as
initial proofreading etc, is unnecessary, use the AD conversion
connection mode.
•The current integrator starts current integration in the low-speed
clock 1-2 cycles, after setting the current integrate enable bit to
“1”. After setting the current integrate enable bit to “0”, initializa-
tion of 1-2 cycle period of a low-speed clock and an internal
circuit is performed. Do not enable the current integrator again in
this period.
•After the current integrate enable bit is set to “1”, current integra-
tion starts with a delay of 1 to 2 cycles of a low-speed clock. As
for the period for 1 to 2 cycle of the low-speed clock immediately
after setting the current integrate enable bit to “0”, the internal cir-
cuit is initialized. Do not enable the current integrator again in this
period.
Table 10 Mode switch timing
Current integrate mode
Calibration mode
12.5 ms setting
15.26 ms setting
31.25 ms setting
62.5 ms setting
Mode switch timing
Period for about 62.5 ms after interrupt occurrence of last integrate period
Period for about 31.25 ms after interrupt occurrence of last integrate period
Period for about 15.625 ms after interrupt occurrence of last integrate period
Period for about 7.8127 ms after interrupt occurrence of last integrate period
Rev.1.01 Aug 02, 2004 page 42 of 96