peb20534 Infineon Technologies Corporation, peb20534 Datasheet - Page 125

• Manufacturer Part Number: peb20534
• Description: Dma Supported Serial Communication Controller With 4 Channels
• Manufacturer: Infineon Technologies Corporation

PEB 20534
PEF 20534
Multi Function Port (MFP)
automatically (like SSCERI), but rather must be cleared by software after servicing. This
allows to service some error conditions via interrupt, while the others may be polled by
software.
Note: The error interrupt handler must clear the associated (enabled) errorflag(s) to
prevent repeated interrupt requests.
A Receive Error (Master or Slave mode) is detected, when a new data frame is
completely received, but the previous data was not read out of the Receive Buffer
register SSCRB. This condition sets the error flag SSCRE and, when enabled via
SSCREN, the error interrupt request flag SSCERI. The old data in the receive buffer
SSCRB will be overwritten with the new value and is unretrievably lost.
A Phase Error (Master or Slave mode) is detected, when the incoming data at pin MRST
(master mode) or MTSR (slave mode), sampled with the same frequency as the CPU
clock, changes in a range between one sample before and two samples after the latching
edge of the clock signal (refer to section ’Clock Control’). This condition sets the error
flag SSCPE and, when enabled via SSCPEN, the error interrupt request flag SSCERI.
A Baud Rate Error (Slave mode) is detected, when the incoming clock signal deviates
from the programmed baud rate by more than 100%, i.e., it has a value of either more
than double or less than half of the expected baud rate. This condition sets the error flag
SSCBE and, when enabled via SSCBEN, the error interrupt request flag SSCEIR.
Using this error detection capability requires that the slave's baud rate generator is
programmed to the same baud rate as the master device. This feature allows to detect
false additional, or missing pulses on the clock line (within a certain frame).
If this error condition occurs and bit SSCAREN=’1’, an automatic reset of the SSC will
be performed. This is done to reinitialize the SSC, when too few or too many clock pulses
have been detected.
A Transmit Error (Slave mode) is detected, when a transfer was initiated by the master
(shift clock gets active), but the transmit buffer SSCTB of the slave was not updated
since the last transfer. This condition sets the error flag SSCTE and, when enabled via
SSCTEN, the error interrupt request flag SSCERI. If a transfer starts while the transmit
buffer is not updated, the slave will shift out the 'old' contents of the shift register, which
are usually the data received during the last transfer.
This may lead to the corruption of the data on the transmit/receive line in half-duplex
mode (open drain configuration), if this slave is not selected for transmission. This mode
requires that slaves not selected for transmission only shift out ’ones’, i.e. their transmit
buffers must be loaded with 'FFFF
' prior to any transfer.
H
Data Sheet
125
2000-05-30