Image Processing Reference
In-Depth Information
As far as resource management is concerned, the HIS I/O library relies on the services provided by
OSEK-operating systems. he I/O drivers [] standardized by HIS are drivers for digital I/O, pulse
width modulation (PWM), pulse width demodulation, analog/digital converters (ADC), watchdog
timer, capture compare timers, EEPROM drivers, and flash drivers.
18.4.3 Flash Driver
he HIS standardized flash driver component [] provides defined services (including a correspond-
ing API) for the initialization of the flash driver component, the de-initialization of the flash driver
component, the erasing of the flash memory, and the writing to the flash memory. Hereby, the job of
the flash driver is to provide a logical abstraction from the physical organization of the flash memory
(e.g., segmentation, banking, a.s.o.). The HIS flash driver is designed to be used as a driver for the
HIS I/O library. Conventional application areas for the HIS flash driver are the flash programming
services of XCP (see Section ..) and ISO diagnostics (see Section ..)
18.4.4 CAN Driver
The HIS CAN driver [] is an implementation of a data link layer for CAN networks. The HIS
CAN driver provides a uniform interface for the reception and the transmission of frames on the
CAN network and thus abstracts from the peculiarities of the underlying buffer configurations of the
respective CAN controller (full CAN vs. basic CAN a.s.o.). he main services provided by the CAN
driver are the following:
Frame reception
: The CAN driver retrieves received frames from the hardware buffers of the CAN
controller and informs upper software layers about the frame reception.
Frame transmission
: On request of higher software layers, the CAN driver transfers frames to be
transmitted into the hardware buffers of the CAN controller and informs higher software layers about
the successful transmission of these frames.
Wakeup service
: If supported by the respective CAN controller, the CAN driver provides services
to put the CAN controller in a special low-power mode (the sleep mode). In case a CAN controller
transits from sleep mode (due to traffic on the communication media) back into the normal operation
mode, the CAN driver informs the higher software layers about this event.
Error handling
: In case fatal errors occur on the CAN communication media, the CAN driver informs
the higher software layers about these errors.
Note, however, that the HIS CAN driver does not provide an I/O library compliant interface!
18.5 ISO
Some of the software layers used for CAN networks in today's cars have been standardized by the
ISO. he most prominent of these software layers are the following:
Transport layer
(
ISO/DIS -.
): -.):This layer provides “unacknowledged segmented data transfer
(USDT)” to all higher layers and thus facilitates exchange of data amounts larger than the maximum
transfer unit (MTU) of the underlying communication system.
Diagnostics—KWP
(
ISO/DIS -
)
and UDS
(
ISO/DIS -
): Both the Keyword Protocol
(KWP) and the unified diagnostic services (UDS) define diagnostic services which “allow
a tester device to control diagnostic functions” in an ECU via a serial data link.
