pef2045 Infineon Technologies Corporation, pef2045 Datasheet - Page 13

• Manufacturer Part Number: pef2045
• Description: Memory Time Switch Cmos Mtsc
• Manufacturer: Infineon Technologies Corporation

2.1
Preparation of the Input Data
The PEx 2045 works in 2048-, 4096- or 8192-kbit/s PCM systems. The frame frequency is 8000 Hz
in all 3 types of systems. Therefore a frame consists of 32-, 64- or 128 time-slots of 1 byte each,
respectively. In order to fill the speech memory, which has a fixed capacity of 512 channels, either
16-, 8- or 4 input lines are necessary, respectively. Thus, in 4- and 8-MHz systems only some of the
16 input lines can be used.
Moreover, the PEx 2045 can also work with two different input data rates simultaneously. In this
case some of the PCM input lines operate at one data rate, while others operate at another.
Table 1 states how many input lines are operating at the different data rates for all possible input
data rate combinations. In the following they will be referred to as input modes.
The input mode the PEx 2045 is actually working in has to be programmed into the mode register,
bits MI1, MI0, MO1, MO0. In chapter 4.1 you will find a complete description which input line is
connected to which system, for each of the input modes.
Table 1
Possible Input Modes
Input Modes
16
8
4
2
4
The PEx 2045 runs with either a 4096- or a 8192-kHz device clock as selected with CFG:CPS. Data
rates and clock frequencies may be combined freely. However, processing 8192-kbit/s data, a
8192-kHz clock must be supplied.
The preparation of the input data according to the selected input mode is made in the input buffer.
It converts the serial data of a time-slot to parallel form.
In standard configuration time-slot 0 begins with the rising edge of the SP pulse as shown in upper
half of figure 9 denoted CSR: (0000XXXX).
Semiconductor Group
8192
4096
Basic Functional Principles
+
+
2048
4096
8192
8
8
2048
2048
kbit/s
kbit/s
kbit/s
kbit/s
kbit/s
13
Type
Single mode
Single mode
Single mode
Mixed mode
Mixed mode
PEB 2045
PEF 2045