4TS68C429A 2120A–HIREL–08/02
Package See “Package Mechanical Data” on page 40 and “Terminal Connections” on page 41.
Figure 1. Signal Description
Pin Name Type Function
A0-8 I Address bus. The add ress bu s is used to select one of the internal registers during a processor
read or write cycle.
D0-15 I/O This bi-d irectiona l bus is used to re ceive data from or transmit d ata to an intern al register during a
process or re ad or write cyc le. Du ring an in terru pt ac k now l edg e cy cl e, th e ve cto r number is given
on the lower data bus (D0 - D7).
CS I Chip select (active low). This input is used to select the chip for internal register access.
LDS I Lower data strobe. This input (active low) validates lower data during R/W access (D0-D7).
UDS I Upper data strobe. This input (active low) validates upper data during R/W access (D8-D15).
R/W I Read/write. This input defines a data transfer as a read (high) or a write (low) cycle.
DTACK O Data transfer acknowledge. If t he bus cycle is a processor rea d, the chip a s serts DTACK to
indicate that the information on the data bus is valid. If the bus cycle is a processor write, DTACK
acknowl edges the a cceptanc e of the data b y the MRT . DTACK will be asserted during chi p select
access (CS asserted) or interrup t acknowle dge cycle (IACKTX or IACKRK asserted).
IRQTX O Interrupt transmit request. This open drain output signals to the processor that an interrupt is
pending from the transmission part of the MRT. There are 6 causes that can generate an
inter rupt requ es t (2 per chann el: FIFO empty and end of transmissi on).
IACKTX I Interrupt transmit acknowledge. If IRQTX is active, the MRT will begin an interrupt acknowledge
cycle. The MRT will generate a vector number to the processor which is the highest priority
channel requesting interrupt service.
IEITX I Interrupt transmit enable in. This input, together with IEOTX signal, provides a daisy chained
interrupt structure for a vectored scheme. IEITX (active low) indicates that no higher priority
device is requesting interrupt service.
IEOTX O Interrupt transmit enable out. This output, together with IEITX signal, provides a daisy chained
interrupt structure for a vectored interrupt scheme. IEOTX (active low) indicates to lower priority
devices that neither the TS68C429A nor any highest priority peripheral is requesting an interrupt.
IRQRX O Interrupt transmit request. This open drain output signals to the processor that an interrupt is
pending from the receiving part of the chip. There are 9 causes that can generate an interrupt
request (1 per channel: valid message received, and 1 for bad parity on a received message).
IACKRX I Interrupt receive acknowledge. Same function as IACKTX but for receiver part.
IEIRX I Interrupt receive enable in. Same function as IEITX but for receiver part.
IEORX I Interrupt receive enable out. Same function as IEOTX but for receiver part.
TX1H O Transmission “1” line of the channel 1.
TX1L O Transmission “0” line of the channel 1.
TX2H O Transmission “1” line of the channel 2.
TX2L O Transmission “0” line of the channel 2.
TX3H O Transmission “1” line of the channel 3.
TX3L O Transmission “0” line of the channel 3.
RX1H I Rec ei vi ng “1” line of the chann el 1.
RX1L I Rec ei vi ng “0” line of the chann el 1.
RX2H I Rec ei vi ng “1” line of the chann el 2