PEB20534H-10V2.1 Infineon Technologies, PEB20534H-10V2.1 Datasheet - Page 197

• Manufacturer Part Number: PEB20534H-10V2.1
• Description: Communication Controller 208-Pin FQFP
• Manufacturer: Infineon Technologies

Figure 73 shows an SCC as a DTE connected to a DCE (MODEM equipment).
The RTS
directional flow control. So when the DTE-A’s receiver threshold is reached, the RTS
signal goes active ’HIGH’ which is sensed by the DCE and it stops transmitting. Similarly
if the DCE’s receiver threshold is reached, it deactivates the CTS
the DTE to stop transmission. These types of DCEs have fairly deep buffers to ensure
that it can continue to receive data from the line even though it is unable to pass the data
to the DTE for short periods of time. Note that a SCC can also be used in the DCE
equipment as shown. Exchange of signals (e.g. RTS to CTS) is necessarily inside the
DCE equipment.
Figure 73
RTS and CTS are used to indicate when the local receiver’s buffer is nearly full. This
alerts the far end transmitter to stop transmission.
The combination of transmitter and receiver out-of-band control features mentioned
above enables data to be exchanged between two devices without software intervention
for flow control.
Data Sheet
DTE A
1) Some of the newer MODEMs support bi-directional flow control.
A
feeds the RTS
Out-of-Band DTE-DCE Bi-directional Flow Control
DSCC4
TxD
RxD
RTS
CTS
B
input of the DCE (MODEM equipment) that supports bi-
RS232c Signals
(drivers not shown)
TxD
RxD
RTS
CTS
197
DCE
B
Detailed Protocol Description
MODEM
DSCC4
1)
B
(’HIGH’) and causes
RTS
CTS
TxD
RxD
PEB 20534
PEF 20534
2000-05-30
A