AcroPack Series AP560
CAN Bus Interface Module
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Acceptance filters can be set up to accept or reject specific messages into the
FIFO and all interrupt flags are set as required in the usual way. While in this
mode, any bus activity is ignored. Loopback is activated by programming the
MODE<2:0> bits to <001> in the CTRL0 register.
Monitor Mode
Monitor mode (also known as listen-only or silent mode) allows the HI-3111
to monitor all bus activity without disturbing the bus. No messages or
dominant bits (such as ACK or active error frame bits) are transmitted to the
bus while in this mode. Also, the error counters are reset and deactivated.
Messages from the bus are received in the same way as Normal Mode and
messages that are not acknowledged by another node on the bus are ignored
i.e. any frame containing an error will be ignored. Acceptance filters can be
set up to reject or accept specific messages into the FIFO and all interrupt
flags are set as required in the usual way. Monitor mode is activated by
programming the MODE<2:0> bits to <010> in the CTRL0 register.
Sleep Mode
The HI-3111 can be placed in a low power sleep mode if there is no bus
activity and the transmit FIFO is empty. In this mode, the internal oscillator
and all analog circuitry (transceiver) are off, drawing typically less than 20µA.
Note that the SPI bus is active during sleep mode, so it is possible for the host
to communicate with the HI-3111 while it is asleep (e.g. load transmit FIFO).
Sleep mode is exited by selecting an alternative mode of operation, or
automatic wake up following bus activity can be enabled by setting the
WAKEUP bit in the CTRL0 register - in this case a low power receiver monitors
the bus for a detectable dominant bit. The device will wake up in Monitor
Mode.
Sleep mode is activated by programming the MODE<2:0> bits to <011> in the
CTRL0 register. However, the actual mode change will only occur whenever
the CAN bus is quiet. If the chip is transmitting, the mode change is delayed
until the transmission is complete. If there is bus activity, the mode change is
delayed until the receiver protocol control detects an inter-message gap.
CAN PROTOCOL OVERVIEW
The HI-3111 supports Standard, Extended and Remote Frames, as defined in
the CAN specification IS0 11898-1:2003(E) (also known asCAN2.0B).
BIT ENCODING
CAN frames are encoded according to the Non-Return-To-Zero (NRZ) method
with bit stuffing. NRZ means that the generated bit level is constant during
the total bit time and consecutive bits do not return to a neutral or rest
condition.
Содержание AcroPack AP560
Страница 28: ...AcroPack Series AP560 CAN Bus Interface Module 28 Figure 2 Standard Data Frame...
Страница 30: ...AcroPack Series AP560 CAN Bus Interface Module 30 Figure 3 Extended Data Frame...
Страница 32: ...AcroPack Series AP560 CAN Bus Interface Module 32 Figure 4 Remote Frame...
Страница 34: ...AcroPack Series AP560 CAN Bus Interface Module 34 Figure 5 Error Frame...