PPC34C60 datasheet(50/58 Pages) SMSC

50 / 58 page

SMSC DS – PPC34C60

Page 50

Rev. 06/01/2001

ADVANCED INFORMATION

PARAMETER

MIN

TYP

MAX

UNITS

At the completion of the ECP reverse transfer cycle the

PPC34C60 either places another valid data byte on the data

lines or if it has no more data to send goes into the idle state

driving undefined data onto the parallel port bus lines. As long

as the port is in the reverse transfer mode, the PPC34C60 will

always return data when a byte is requested. Once HOST

MAX BLOCK byte-count has been reached, the PPC34C60

will present "pad" bytes to the host. The Host will discard any

extra bytes received. The extra "pad" bytes are useful to

provide alignment to wider buses.

125

[3 SCLK]

167

[4 SCLK]

The Host requests that the parallel port be placed back into

the forward direction by deasserting nINIT, and in response to

this the PPC34C60 will terminate any ongoing data transfer

and place the data bus HD[0:7] in a high impedance state and

deassert the BSY line.

125

[3 SCLK]

167

[4 SCLK]

t10 After releasing the bus, the PPC34C60 acknowledges that it

has relinquished the bus by asserting the PE signal.

125

[3 SCLK]

t11 After the PPC34C60 has indicated that it has relinquished the

bus, the Host may drive the data bus.

500

PPC34C60 Scheda tecnica(PDF) 50 Page - SMSC Corporation