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| 型号： | M38507F8AFP |
| 元件分类： | 微控制器/微处理器 |
| 英文描述： | 8-BIT, FLASH, 6.25 MHz, MICROCONTROLLER, PDSO42 |
| 封装： | 8.40 X 17.50 MM, 0.80 MM PITCH, PLASTIC, SSOP-42 |
| 文件页数： | 48/59页 |
| 文件大小： | 885K |
| 代理商： | M38507F8AFP |
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Rev.2.13
Apr 17, 2009
Page 52 of 56
REJ03B0125-0213
3850 Group (Spec.A QzROM version)
NOTES ON PERIPHERAL FUNCTIONS
Notes on Input and Output Ports
1. Notes in standby state
In standby state*1, do not make input levels of an I/O port
“undefined”, especially for I/O ports of the N-channel open-
drain. When setting the N-channel open-drain port as an output,
do not make input levels of an I/O port “undefined”, too.
Pull-up (connect the port to VCC) or pull-down (connect the port
to VSS) these ports through a resistor.
When determining a resistance value, note the following points:
External circuit
Variation of output levels during the ordinary operation
<Reason>
When setting as an input port with its direction register, the
transistor becomes the OFF state, which causes the ports to be
the high-impedance state.
Accordingly, the potential which is input to the input buffer in a
microcomputer is unstable in the state that input levels of an I/O
port are “undefined”. This may cause power source current.
In I/O ports of N-channel open-drain, when the contents of the
port latch are “1”, even if it is set as an output port with its
direction register, it becomes the same phenomenon as the case
of an input port.
NOTES:
4. Standby state:
stop mode by executing STP instruction
wait mode by executing WIT instruction
2. Modifying output data with bit managing instruction
When the port latch of an I/O port is modified with the bit
managing instruction*2, the value of the unspecified bit may be
changed.
<Reason>
The bit managing instructions are read-modify-write form
instructions for reading and writing data by a byte unit.
Accordingly, when these instructions are executed on a bit of the
port latch of an I/O port, the following is executed to all bits of
the port latch.
As for bit which is set for input port:
The pin state is read in the CPU, and is written to this bit after
bit managing.
As for bit which is set for output port:
The bit value is read in the CPU, and is written to this bit after
bit managing.
Note the following:
Even when a port which is set as an output port is changed for
an input port, its port latch holds the output data.
As for a bit of which is set for an input port, its value may be
changed even when not specified with a bit managing
instruction in case where the pin state differs from its port
latch contents.
NOTES:
5. Bit managing instructions: SEB and CLB instructions
Termination of Unused Pins
1. Terminate unused pins
(1) I/O ports:
Set the I/O ports for the input mode and connect them to VCC
or VSS through each resistor of 1 k
to 10 k. In the port
which can select a internal pull-up resistor, the internal pull-up
resistor can be used.
Set the I/O ports for the output mode and open them at “L” or
“H”.
When opening them in the output mode, the input mode of the
initial status remains until the mode of the ports is switched
over to the output mode by the program after reset. Thus, the
potential at these pins is undefined and the power source
current may increase in the input mode. With regard to an
effects on the system, thoroughly perform system evaluation
on the user side.
Since the direction register setup may be changed because of a
program runaway or noise, set direction registers by program
periodically to increase the reliability of program.
(2) The AVSS pin when not using the A/D converter:
When not using the A/D converter, handle a power source pin
for the A/D converter, AVSS pin as follows:
AVSS: Connect to the VSS pin.
2. Termination remarks
(1) Input ports and I/O ports:
Do not open in the input mode.
<Reason>
The power source current may increase depending on the first-
stage circuit.
An effect due to noise may be easily produced as compared
with proper termination (1) in 1 shown on the above.
(2) I/O ports:
When setting for the input mode, do not connect to VCC or VSS
directly.
<Reason>
If the direction register setup changes for the output mode
because of a program runaway or noise, a short circuit may occur
between a port and VCC (or VSS).
(3) I/O ports:
When setting for the input mode, do not connect multiple ports in
a lump to VCC or VSS through a resistor.
<Reason>
If the direction register setup changes for the output mode
because of a program runaway or noise, a short circuit may occur
between ports.
At the termination of unused pins, perform wiring at the
sh ortest possible distance (2 0 mm or less) fr om
microcomputer pins.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| M38507F8AFP#U1 | 功能描述:IC 740/3850 MCU FLASH 42SSOP RoHS:是 类别:集成电路 (IC) >> 嵌入式 - 微控制器， 系列:740/38000 产品培训模块:CAN Basics Part-1 CAN Basics Part-2 Electromagnetic Noise Reduction Techniques Part 1 M16C Product Overview Part 1 M16C Product Overview Part 2 标准包装:1 系列:M16C™ M32C/80/87 核心处理器:M32C/80 芯体尺寸:16/32-位 速度:32MHz 连通性:EBI/EMI，I²C，IEBus，IrDA，SIO，UART/USART 外围设备:DMA，POR，PWM，WDT 输入/输出数:121 程序存储器容量:384KB（384K x 8） 程序存储器类型:闪存 EEPROM 大小:- RAM 容量:24K x 8 电压 - 电源 (Vcc/Vdd):3 V ~ 5.5 V 数据转换器:A/D 34x10b，D/A 2x8b 振荡器型:内部 工作温度:-20°C ~ 85°C 封装/外壳:144-LQFP 包装:托盘 产品目录页面:749 (CN2011-ZH PDF) 配用:R0K330879S001BE-ND - KIT DEV RSK M32C/87 |
| M38507F8AFP#W1 | 制造商:Renesas Electronics Corporation 功能描述:MCU 3/5V 32K PB-FREE 42-SSOP T&R - Tape and Reel |
| M38507F8FP | 制造商:Renesas Electronics Corporation 功能描述:MCU 8-Bit 740 CISC 32KB Flash 5V 42-Pin SSOP 制造商:Renesas Electronics Corporation 功能描述:MCU 8BIT 740 CISC 32KB FLASH 5V 42SSOP - Trays |
| M38507F8FP#U1 | 制造商:Renesas Electronics Corporation 功能描述:MCU 8BIT 740 CISC 32KB FLASH 5V 42SSOP - Trays |
| M38507F8FP#W1 | 制造商:Renesas Electronics Corporation 功能描述:FLASH 8-BIT 2.7 TO 5.5V PBFREE |
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