UPD78F0890GK(A)-GAJ-AX NEC, UPD78F0890GK(A)-GAJ-AX Datasheet - Page 608

• Manufacturer Part Number: UPD78F0890GK(A)-GAJ-AX
• Description: 8BIT MCU, 128K FLASH, 7K RAM, LQFP
• Manufacturer: NEC

Specifications of UPD78F0890GK(A)-GAJ-AX

• Controller Family/series: UPD78F
• No. Of I/o's: 55
• Ram Memory Size: 7KB
• Cpu Speed: 20MHz
• No. Of Timers: 10
• No. Of Pwm: RoHS Compliant
• Core Size: 8bit
• Program Memory Size: 128KB
• Oscillator Type: External, Internal

(1) Signal collision
(2) Malfunction of other device
608
If the dedicated flash memory programmer (output) is connected to a pin (input) of a serial interface connected to
another device (output), signal collision takes place. To avoid this collision, either isolate the connection with the
other device, or make the other device go into an output high-impedance state.
If the dedicated flash memory programmer (output or input) is connected to a pin (input or output) of a serial
interface connected to another device (input), a signal may be output to the other device, causing the device to
malfunction. To avoid this malfunction, isolate the connection with the other device.
78K0/FE2
Input pin
78K0/FE2
78K0/FE2
Figure 24-9. Signal Collision (Input Pin of Serial Interface)
Pin
Pin
In the flash memory programming mode, the signal output by the device
collides with the signal sent from the dedicated flash memory programmer.
Therefore, isolate the signal of the other device.
If the signal output by the 78K0/FE2 in the flash memory programming
mode affects the other device, isolate the signal of the other device.
If the signal output by the dedicated flash memory programmer in the flash
memory programming mode affects the other device, isolate the signal of
the other device.
Figure 24-10. Malfunction of Other Device
Signal collision
CHAPTER 24 FLASH MEMORY
User’s Manual U17554EJ4V0UD
Dedicated flash memory
programmer connection pin
Dedicated flash memory
programmer connection pin
Dedicated flash memory
programmer connection pin
Other device
Output pin
Other device
Other device
Input pin
Input pin