peb20525 Infineon Technologies Corporation, peb20525 Datasheet - Page 47

• Manufacturer Part Number: peb20525
• Description: 2 Channel Serial Optimized Communication Controller For Hdlc/ppp
• Manufacturer: Infineon Technologies Corporation

3.2.3
The SEROCCO-H includes an internal Oscillator (OSC) as well as two independent
Baud Rate Generators (BRG) and two Digital Phase Locked Loop (DPLL) circuits.
The transmit and receive clock can be generated either
• externally, and supplied directly via the RxCLK and/or TxCLK pins
• internally, by selecting
There are a total of 14 different clocking modes programmable via bit field ’CM’ in
register CCR0L, providing a wide variety of clock generation and clock pin functions, as
shown in
The transmit clock pins (TxCLK) may also be configured as output clock and control
signals in certain clock modes if enabled via bit ’TOE’ in register CCR0L.
The clocking source for the DPLL’s is always the internal channel specific BRG; the
scaling factor (divider) of the BRG can be programmed through
registers.
There are two channel specific internal operational clocks in the SCC:
One operational clock (= transmit clock) for the transmitter part and one operational clock
(= receive clock) for the receiver part of the protocol logic.
Note: The internal timers always run using the internal transmit clock.
Table 7
Type
Receive
Clock
Transmit
Clock
Data Sheet
(called external clock modes)
– the internal oscillator (OSC) and/or the channel specific baud rate generator (BRG)
– the internal DPLL, recovering the receive (and optionally transmit) clock from the
(called internal clock modes)
receive data stream.
Table
Clocking System
Overview of Clock Modes
8.
Source
RxCLK Pins
OSC,
DPLL,
BRG,
TxCLK Pins,
RxCLK Pins
OSC,
DPLL,
BRG/BCR,
BRG
Clock
47
Generation
Externally
Internally
Externally
Internally
Functional Overview
Clock Mode
0, 1, 4, 5
2, 3a, 6, 7a
3b, 7b
0a, 2a, 4, 6a
1,5
3a, 7a
2b, 6b
0b, 3b, 7b
BRRL
PEB 20525
PEF 20525
and
2000-09-14
BRRH