SC68C752B datasheet(16/49 Pages) PHILIPS

Part #	SC68C752B

Description	5 V, 3.3 V and 2.5 V dual UART, 5 Mbit/s (max.), with 64-byte FIFOs and Motorola uP interface

PDF	49 Pages

Scroll/Zoom	100%

Manufacturer	PHILIPS [NXP Semiconductors]

Direct Link	http://www.nxp.com

Logo

16 / 49 page

SC68C752B_3

Product data sheet

Rev. 03 — 29 November 2005

16 of 49

Philips Semiconductors

SC68C752B

5 V, 3.3 V and 2.5 V dual UART, 5 Mbit/s (max.), with 64-byte FIFOs

6.6 DMA operation

There are two modes of DMA operation, DMA mode 0 or DMA mode 1, selected by

FCR[3].

In DMA mode 0 or FIFO disable (FCR[0] = 0) DMA occurs in single character transfers. In

DMA mode 1, multi-character (or block) DMA transfers are managed to relieve the

processor for longer periods of time.

6.6.1 Single DMA transfers (DMA mode 0/FIFO disable)

Figure 10 shows TXRDY and RXRDY in DMA mode 0/FIFO disable.

6.6.1.1

Transmitter

When empty, the TXRDY signal becomes active. TXRDY will go inactive after one

character has been loaded into it.

6.6.1.2

Receiver

RXRDY is active when there is at least one character in the FIFO. It becomes inactive

when the receiver is empty.

Fig 10. TXRDY and RXRDY in DMA mode 0/FIFO disable

wrptr

FIFO EMPTY

TXRDY

rdptr

FIFO EMPTY

RXRDY

002aaa232

at least one

location filled

at least one

location filled

TXRDY

SC68C752B Datasheet(PDF) 16 Page - NXP Semiconductors