UPD72001C datasheet(10/40 Pages) NEC

10 / 40 page

µPD72001-11, 72001-A8

(b) Non-vector mode (CR2A: D7 = “0”)

In this mode, the PRI pin controls only the generation of interrupts because the INTAK sequence is not used.

If an interrupt vector output mode other than Type A-3 and Type B-2 is selected, generation of an interrupt

signal is enabled if “L” is input to the PRI pin. The interrupt signal is not generated if “H” is input to PRI.

If an interrupt daisy chain is configured, inputting “L” to this pin indicates that a device having a higher priority

does not acknowledge interrupt processing or does not have an interrupt request, and only the MPSC with

“L” input to its PRI pin can generate an interrupt.

(13) PRO (Priority Output) ... Output

This pin is used when an interrupt daisy chain is configured. This output pin is active-low, and controls generation

of interrupts requests from a device with a lower priority. Usually, this pin is used along with the PRI pin, and

its operation is as follows:

When PRI = “H”, PRO = “H”

When PRI = “L”, PRO goes “H” if there is an interrupt request, and goes “L” if there is no interrupt request.

(14) DRQTXA (DMA Request TXA) ... Output

This pin outputs a DMA request to a DMA controller. This pin is active-high. It goes “H” if the transmitter of channel

A has entered the TX Buffer Empty status. The condition under which this pin goes “H” differs as follows depending

on the setting of the CR1 and D2 bits.

CR1: D2 = “0”: The DRQTXA pin goes “H” when the transmitter has entered the TX Buffer Empty status after

the first transmit data has been written. It does not go “H” when the transmitter has entered

the TX Buffer Empty status after reset.

CR1: D2 = “1”: The DRQTXA pin goes “H” when the transmitter has entered the TX Buffer Empty status.

This signal is reset when transmit data has been written to channel A.

(15) DRQRXA (DMA Request RXA) ... Output

This pin outputs a DMA request to a DMA controller. This pin is active-high and goes “H” if the receiver of channel

A has entered the RX Character Available status. This signal is reset only when receive data has been read from

channel A.

(16) DTRA/DRQTXB (Data Terminal Ready A/DMA Request TXB) ... Output

The function of this pin is changed as follows depending on the setting of CR2A: D1 and D0.

(a) When CR2A: D1, D0 = “0, 0” or “0, 1”

This pin functions as the DTRA pin. This pin is a general-purpose output pin and can be used to control a

modem, etc. The operation of the DTRA pin is as follows:

When CR5A: D7 = “0”, DTRA = “H”

When CR5A: D7 = “1”, DTRA = “L”

(b) When CR2A: D1, D0 = “1, 0”

This pin functions as the DRQTXB output pin. The function of this pin is the same as the DRQTXA pin, except

this pin is used with channel B.

(17) DTRB/DRQRXB (Data Terminal Ready B/DMA Request RXB) ... Output

The function of this pin changes as follows depending on the setting of CR2A: D1 and D0.

UPD72001C 데이터시트(PDF) 10 Page - NEC