UPD72001C datasheet(7/40 Pages) NEC

7 / 40 page

µPD72001-11, 72001-A8

1. PIN FUNCTIONS

The functions of the MPSC can be broadly classified into “system interface functions” that control interfacing with

the host system, and “transmission/reception functions” to transmit or receive data. This section explains the functions

of the pins of the MPSC by classifying the pins into those related to system interfacing and those related to transmission

and reception.

Hereafter, “H” (voltage level satisfying VIH in the case of an input pin, or voltage level satisfying VOH in the case

of an output pin) and “L” (voltage level satisfying VIL in the case of an input pin, or voltage level satisfying VOL in the

case of an output pin) are used to indicate the input/output status of a pin.

1.1 Pins Related to System Interface

(1) VDD

Supply voltage pin

(2) GND

GND pin

(3) RESET ... Input

This pin inputs a signal from an external device to reset the MPSC. When “L” is input to this pin for the duration

of 2 clock cycles (2tCYK) or longer, the MPSC is reset (this is called system reset).

As a result of system reset, the transmitter, receiver, and interrupt/DMA functions of the MPSC are disabled, and

the TXD pin and general-purpose output pins go high. In this case, because all bits of the control register (CR)

are also reset, CR must be set again if a system reset has been executed.

Table 1-1 shows the status of each pin at system reset, in comparison with the pin status at channel reset (CR0:

D5, D4, D3 = “0, 1, 1”).

The MPSC automatically enters the standby mode at system reset, lowering the power consumption from that

in the normal operation mode.

UPD72001C Datasheet(PDF) 7 Page - NEC