+/+…when timing is critical
C9829B
Low EMI Clock Generator for Intel 133MHz/3DIMM Chipset Systems
Approved Product
Power on Bi-Functional Pins (Cont.)
Pin 32 (TS# / PD#) is a bi-functional pin, See Fig.6. If this pin is externally held low during power up, the device is forced
into tristate/or test mode depending on the state of Sel0.
In Tristate mode, all outputs assume the high impedance (Hi-Z) state. In test, all outputs toggle as described in table 2,
page 3.
All outputs remain in their Hi-Z state (or test mode) until the external signal applied to pin 32 is released (set high). After
a minimum of 1.5mS from a stable 3.3V power supply or until TS# is released (whichever is longer), pin 32 changes
from a tristate controller (TS#) to Power Down controller (PD#) and remains in that function unless otherwise
programmed through the I2C to return to the TS# function by setting byte3, bit1 to a “0”. Once the TS# signal is released
(high), pin 32 may be toggled repetitively to force the device in and out of power down mode.
The device is considered in power down when PD# is asserted low, consequently, all clocks are stopped synchronously
and after the completion of a full period (glitch-free).
3.3V
Power
Supply
TS# function
TS# asserted
low
TS# released
PD# asserted low
PD# released
TS#
ς
TS# function
Default High
PD#
ς
I2C,
Byte3,
Bit1
programmed Low
Toggle
Hi-Z
Hi-Z
Output
Clock
Power Down
ς
ς
Fig.6
2-Wire I2C Control Interface
The 2-wire control interface implements a read/write slave only interface according to Philips I²C specification. (See Fig.
7 below). The device can be read back by using standard I2C command bytes. Sub addressing is not supported, thus all
preceding bytes must be sent in order to change one of the control bytes. The 2-wire control interface allows each clock
output to be individually enabled or disabled. 100 Kbits/second (standard mode) data transfer is supported.
INTERNATIONAL MICROCIRCUITS, INC. 525 LOS COCHES ST.,
MILPITAS, CA 95035, USA. TEL: 408-263-6300, FAX 408-263-6571
http://www.imicorp.com
Rev 1.3
4/12/2000
Page 7 of 20
CYPRESS [ CYPRESS ]
