TCM4400 Datasheet, PDF (33/72 Pages) Texas Instruments – GSM/DCS BASEBAND AND VOICE A/D AND D/A RF INTERFACE CIRCUIT

3.3 Microcontroller Unit Serial Interface Timing Considerations
Figure 3–3 shows the timing diagram for the microcontroller unit (MCU) serial interface.
The MCU is compliant with 8-bit standard synchronous serial ports. The microcontroller operates on 16-bit
words; this interface consists of four pins.
UCLK: A clock provided by the microcontroller to control access to baseband, voice band, and
auxiliary functions registers
UDR: An input terminal to control read and write access to baseband, voice band, and auxiliary
functions registers
UDX: An output terminal to transmit data from read access of baseband, voice band, and auxiliary
functions registers
USEL: An input terminal to enable read and write access to baseband, voice band, and auxiliary
functions registers through the microcontroller interface
th10
USEL
tsu10
ÎÎÎÎÎÎÎÎÎ _UCLK
tc
th10
UDR^{ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎtsuÎÎÎ11 ÎÎÎ ÎÎÎÎÎÎÎÎÎ}
th11 _{ÎÎÎÎÎÎÎÎÎ}
tv_{ÎÎÎ2 ÎÎÎÎÎÎÎÎÎ}^th9_{ÎÎÎÎÎÎ}
tv1
th12
Hi-Z
Hi-Z
UDX
Figure 3–3. Microcontroller Unit Serial Interface Timing Waveforms
(Mode Rising Edge Without Delay)
3–3