SDA6000 Datasheet, PDF (101/380 Pages) Infineon Technologies AG – Teletext Decoder with Embedded 16-bit Controller

SDA 6000
Interrupt and Trap Functions
channel has in its PEC control register the enabled CL flag and if its transfer count is
more than zero.
Note: With the last transfer of a block transfer (COUNT = 0), the channel link control flag
CL of that channel is cleared in its PECCx register. If the CL channel link flag of
the new (chained) PEC control register is found to be zero, the whole data transfer
is finished and the channel link interrupt is coincidentally a termination interrupt.
The channel link mode is finished and the internal channel toggle flag is cleared
after the last transfer of the block, if the CL flags of both pair channels are cleared.
Additional Interrupt Request Node for Channel Link Interrupts
The PEC unit has one dedicated service request node (trap number) for all channel link
interrupts. This service request node requests CPU interrupt service in case of one or
more channel link request flags and the respective enable control bit being set in the
channel link interrupt subnode control register (CLISNC). These flags indicate a channel
link interrupt condition of linked PEC channels (A and B channels) which requires
support from the CPU. The following channel link interrupt conditions requesting CPU
service are possible:
• In single transfer mode a COUNT value change from 01_H to 00_H in a linked PEC
channel and CL flag is set in the respective PEC control register.
In this case the CPU service is requested to update the PEC control and pointer registers
while the next block transfer is executed (the whole transfer is divided into separately
controlled block transfers). The last block transfer is determined by the missing link bit
in the new (linked) PEC control register. If a new service request hits a linked channel
with count equal to zero and channel link flag disabled, a standard interrupt, as known
from standard PEC channels, is performed.
The channel link interrupt subnode register CLISNC is defined as follows:
Users Manual
5 - 17
2000-06-15