ucb1200 NXP Semiconductors, ucb1200 Datasheet - Page 26

• Manufacturer Part Number: ucb1200
• Description: Advanced Modem/audio Analog Front-end
• Manufacturer: NXP Semiconductors

Philips Semiconductors
The applied clock signal to the SIBCLK pin is used as clock signal inside the UCB1200; all internal clock signals are
derived from that. It is required that the SIBCLK signal is applied if one or more analog or digital functions are activated
in the UCB1200; only the interrupt controller is implemented asynchronously. SIBCLK may be stopped when all digital
and analog functions are disabled; in that case the lowest possible power consumption is met. The SIBCLK should not
be stopped during a SIB frame, but only at the end of the SIB-frame, to ensure that all analog and digital functions are
stopped properly.
Note: The interrupt controller is still active, due to its asynchronous implementation. The UCB1200 can therefore still
generate interrupts to the system controller, when the SIBCLK is stopped.
The generation of the audio and telecom sample clocks requires that the SIBCLK signal is symmetrical: a non
symmetrical SIBCLK will lead to non equidistant sample moments, when an odd frequency divisor is set in either of the
audio or telecom control register.
1998 Jul 22
Advanced modem/audio analog front-end
sibdout #1
sibdout #2
sibsync
sibdin
sibclk
bit 0
Fig.21 Serial data transmission of the UCB1200
bit 1
bit 63 bit 64 bit 65
26
bit 126 bit 127 bit 0
Product specification
UCB1200