M37544G2AGP#U0 Renesas Electronics America, M37544G2AGP#U0 Datasheet - Page 72

• Manufacturer Part Number: M37544G2AGP#U0
• Description: IC 740 MCU OTP 8K 32LQFP
• Manufacturer: Renesas Electronics America
• Series: 740/38000r

Specifications of M37544G2AGP#U0

• Core Processor: 740
• Core Size: 8-Bit
• Speed: 8MHz
• Connectivity: SIO, UART/USART
• Peripherals: WDT
• Number Of I /o: 25
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: QzROM
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 6x8b
• Oscillator Type: Internal
• Operating Temperature: -20°C ~ 85°C
• Package / Case: 32-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

REJ03B0108-0103
page 70 of 72
7544 Group (QzROM version)
4. I/O pin function when serial I/O is enabled.
The pin functions of P1
follows according to the setting values of a serial I/O mode selec-
tion bit (bit 6 of serial I/O control register (address 001A
serial I/O synchronous clock selection bit (bit 1 of serial I/O control
register).
(1) Serial I/O mode selection bit → “1” :
Clock synchronous type serial I/O is selected.
• Setup of a serial I/O synchronous clock selection bit
“0” : P1
“1” : P1
• Setup of a S
“0” : P1
“1” : P1
(2) Serial I/O mode selection bit → “0” :
Clock asynchronous (UART) type serial I/O is selected.
• Setup of a serial I/O synchronous clock selection bit
“0”: P1
“1”: P1
• When clock asynchronous (UART) type serial I/O is selected, it
Notes on A/D conversion
1. Analog input pin
Make the signal source impedance for analog input low, or equip
an analog input pin with an external capacitor of 0.01µF to 1µF.
Further, be sure to verify the operation of application products on
the user side.
<Reason>
An analog input pin includes the capacitor for analog voltage com-
parison. Accordingly, when signals from signal source with high
impedance are input to an analog input pin, charge and discharge
noise generates. This may cause the A/D conversion/comparison
precision to be worse.
2. Clock frequency during A/D conversion
The comparator consists of a capacity coupling, and a charge of
the capacity will be lost if the clock frequency is too low. This may
cause the A/D conversion precision to be worse. Accordingly, set
f(X
during A/D conversion.
functions P1
IN
) in order that the A/D conversion clock is 500 kHz or over
2
2
2
2
3
3
pin can be used as a normal I/O pin.
pin turns into an input pin of an external clock.
pin turns into an output pin of a synchronous clock.
pin turns into an input pin of a synchronous clock.
pin can be used as a normal I/O pin.
pin turns into a S
RDY
3
pin. It can be used as a normal I/O pin.
output enable bit (SRDY)
Rev.1.03
2
/S
RDY
CLK
output pin.
and P1
Mar 31, 2009
3
/S
RDY
are switched to as
16
)) and a
3. A/D conversion accuracy
As for AD translation accuracy, on the following operating condi-
tions, accuracy may become low.
(1) Since the analog circuit inside a microcomputer becomes sen-
(2) When V
Notes on Watchdog Timer
1. The watchdog timer is operating during the wait mode. Write
2. The watchdog timer stops during the stop mode. However, the
3. The STP instruction function selection bit (bit 6 of watchdog
Notes on RESET pin
1. Connecting capacitor
In case where the RESET signal rise time is long, connect a ce-
ramic capacitor or others across the RESET pin and the Vss pin.
And use a 1000 pF or more capacitor for high frequency use.
When connecting the capacitor, note the following :
• Make the length of the wiring which is connected to a capacitor
• Be sure to verify the operation of application products on the
<Reason>
If the several nanosecond or several ten nanosecond impulse
noise enters the RESET pin, it may cause a microcomputer fail-
ure.
as short as possible.
user side.
data to the watchdog timer control register to prevent timer un-
derflow.
watchdog timer is running during the oscillation stabilizing time
after the STP instruction is released. In order to avoid the un-
derflow of the watchdog timer, the watchdog timer count source
selection bit (bit 7 of watchdog timer control register (address
0039
timer control register (address 0039
once after releasing reset. After rewriting it is disable to write
any data to this bit.
sitive to noise when V
voltage, accuracy may become low rather than the case
where V
value.
low temperature may become extremely low compared with
that at room temperature. When the system would be used at
low temperature, the use at V
mended.
16
)) before executing the STP instruction.
REF
REF
voltage is lower than [ 3.0 V ], the accuracy at the
voltage and Vcc voltage are set up to the same
REF
voltage is set up lower than Vcc
REF
=3.0 V or more is recom-
16
)) can be rewritten only