M37517F8HP Datasheet, PDF (41/98 Pages) Renesas Technology Corp – SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER

7517 Group
The calibration starts current integration for period selected cali-
bration period selection bit, after discharging electric charge which
remain in integrator's capacitor. After finished calibration period,
value of the discharge (charge) counter is latched to discharge
(charge) counter latch, then current integrate mode bit is cleared
“0”, and current integrate mode is switched to current integrate
mode from calibration mode automatically. At this time the current
integrate interrupt occurs. Which interrupt has occurred current in-
tegrate interrupt for current integrate mode or for calibration mode
can be judged by reading the counter latch content flag. The
counter latch content flag shows the contents of counter latch,
value for current integrate mode or value for calibration mode.
Note that the contents of the counter latch is updated automati-
cally at the end of next current integration or calibration.
sNotes on calibration mode
•After enabling the current integrator, a first-time integrate period
cannot be operated in the calibration mode.
•Do not change the value of the calibration selection bit and the
calibration period selection bits during operation in the calibration
mode.
•When calibration time is set as 125 ms, next current period which
the calibration is completed cannot be operated in the calibration
mode.
•After the current integrator is set to the calibration mode, do not
disable the current integrator until the current period in the calibra-
tion mode is completed.
When current integration is disabled before the current period
completion in the calibration mode after setting “1” to the current
integrate mode bit, the current period of the first time which re-per-
mitted current integration may operate in the calibration mode
regardless of the setting of the current integrate mode bit.
AD conversion connection mode
Setting the AD conversion connection bit to “1”, AD converter
comes to convert the electric charge remained in the integrator ca-
pacitor at the end of current integrate or calibration period. This
makes a fraction of a count possible to measure. When AD con-
version connection bit is “1”, input of AD converter is connected
automatically to the output of the integrator just after the end of
the current integrate or calibration period, and AD conversion
starts. The current integrate interrupt occurs at the end of the AD
conversion. Then remained electric charge in the integrator ca-
pacitor is discharged, and new current integration starts. After AD
conversion completes, the input of the AD conversion is automati-
cally returned previous state.
b7
b0
b7 b6 b5 b4 b3 b2 b1 b0
b7
b0
b15 b14 b13 b12 b11 b10 b9 b8
Discharge counter latch low-order register (000A16)
Discharge counter latch high-order register (000B16)
b7
b0
b7 b6 b5 b4 b3 b2 b1 b0
Charge counter latch low-order register (000C16)
b7
b0
b15 b14 b13 b12 b11 b10 b9 b8
Charge counter latch high-order register (000D16)
b7
b0
Current integrate control register (000E16)
Fig. 47 Current integrator registers
Current integrate mode bit
0 : Current integrate mode
1 : Calibration mode
Calibration selection bits
00 : Zero calibration
01 : Full calibration for discharge
10 : Full calibration for charge
11 : Not used
AD conversion connection bit
0 : Not connect
1 : Connect
Calibration period selection bits
00 : 15.625ms
01 : 31.25ms
10 : 62.5ms
11 : 125ms
Counter latch contents flag
0 : Current integrate data
1 : Calibration data
Current integrate enable bit
0 : Disable
1 : Enable
Rev.1.01 Aug 02, 2004 page 41 of 96