UPD78F9222MC(T)-5A4-A NEC, UPD78F9222MC(T)-5A4-A Datasheet - Page 271

• Manufacturer Part Number: UPD78F9222MC(T)-5A4-A
• Description: 8BIT MCU, 4K FLASH, 256B RAM, 78F9222
• Manufacturer: NEC

Specifications of UPD78F9222MC(T)-5A4-A

• Controller Family/series: UPD78
• No. Of I/o's: 17
• Ram Memory Size: 256Byte
• Cpu Speed: 10MHz
• No. Of Timers: 4
• No. Of: RoHS Compliant
• Core Size: 8bit
• Program Memory Size: 4KB
• Oscillator Type: External, Internal

18.6 Pin Connection on Board
provided on the target system. First provide a function that selects the normal operation mode or flash memory
programming mode on the board.
the same status as immediately after reset. Therefore, if the external device does not recognize the state immediately
after reset, the pins must be processed as described below.
18.6.1 X1 and X2 pins
pins are connected to an external device, a signal conflict occurs. To prevent the conflict of signals, isolate the
connection with the external device.
and thus communication may be disabled depending on the capacitor capacitance. Make sure to isolate the
connection with the capacitor during flash programming.
when it is difficult to isolate the resonator, while a crystal or ceramic resonator is selected as the system clock.
To write the flash memory on-board, connectors that connect the dedicated flash memory programmer must be
When the flash memory programming mode is set, all the pins not used for programming the flash memory are in
The state of the pins in the self programming mode is the same as that in the HALT mode.
The X1 and X2 pins are used as the serial interface of flash memory programming. Therefore, if the X1 and X2
Similarly, when a capacitor is connected to the X1 and X2 pins, the waveform during communication is changed,
Perform the following processing (1) and (2) when on-board programming is performed with the resonator mounted,
(1) Mount the minimum-possible test pads between the device and the resonator, and connect the programmer via
(2) Set the oscillation frequency of the communication clock for writing using the GUI software of the dedicated
the test pad. Keep the wiring as short as possible (refer to Figure 18-4 and Table 18-3).
flash memory programmer.
resonator used, and set the oscillation frequency so that it is outside the range of the resonant frequency ±10%
(refer to Figure 18-5 and Table 18-4).
High-speed internal oscillation clock
External clock
Crystal/ceramic oscillation
clock
Table 18-3. Clock to Be Used and Mounting of Test Pads
Figure 18-4. Example of Mounting Test Pads
Clock to Be Used
Research the series/parallel resonant and antiresonant frequencies of the
CHAPTER 18 FLASH MEMORY
Before resonator is mounted
After resonator is mounted
User’s Manual U16898EJ5V0UD
V
SS
X1
Test pad
X2
Not required
Required
Mounting of Test Pads
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