UPD784026 Renesas Electronics Corporation., UPD784026 Datasheet - Page 73

• Manufacturer Part Number: UPD784026
• Description: 16/8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

2.4 CAUTIONS
(1) When connecting unused pins, if the input/output mode is undefined for an input/output dual-function pin, it should be
(2) In the PD784021, P60 to P63 are in the output high-impedance state during RESET input, but output low level after RESET
(3) In the PD78233 and 78237, the TEST pin is the MODE pin and is fixed high. When changing over from the PD78233/
connected to V
or over upon powering on, and when input/output is switched by software.)
release. Therefore, external circuitry should be designed so that output of low-level signal in the initial state is no problem.
78237, the circuitry must be modified so that this pin is directly connected to V
Some modification is needed if the PD78234/78238 was used with switching between the internal ROM mode and ROM-
less mode performed by MODE pin switching (the TEST pin must be directly connected to V
Modifications examples:
• Incorporate all programs in ROM
• Store all programs in external ROM
• Change the location address of a program previously held in external ROM, shift the address to avoid overlapping internal
ROM, and execute this program from the program in internal ROM
DD
with a resistor of several tens of k (especially when the reset input pin becomes the low-level input voltage
CHAPTER 2 PIN FUNCTIONS
SS
.
SS
).
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