XC2700 Datasheet, PDF (53/62 Pages) Infineon Technologies AG – 16/32-Bit Single-Chip Microcontroller

XC2700 Derivatives
XC2000 Family / Alpha Line
Detailed Errata Description
rem ote
CAN Bus request
rem ote
request
d a ta
d a ta
lo ss of
a rb itration
M ultiC A N
s e tu p
d a ta
o b je c t
s e tu p
d a ta
o b je c t
s e tu p
d a ta
o b je c t
c le a r
NEW DAT
by HW
cle ar set
NEW DAT
by HW
c le a r
NEW DAT
by HW
Figure 6 Loss of Arbitration
OCDS_X.H002 Suspend Mode Behavior for MultiCAN
The MultiCAN module basically provides two mechanisms to stop participation in CAN
bus communication when a suspend request is issued by the OCDS:
Suspend operation of selected CAN nodes
The sensitivity to a suspend request can be individually enabled/disabled for each CAN
node via bit SUSEN in its associated Node Control Register NCRx. With SUSEN = 1_B,
upon a suspend request bit INIT is internally forced to 1_B to disable the CAN node as
soon as it becomes BUS IDLE or BUS OFF. This way, a CAN node correctly finishes a
running CAN frame, but does not start a new one. The network is not blocked due to the
suspend state of one communication partner. All CAN registers can be read and written
in this state since the module clock is not switched off.
Notes
1. Depending on CAN activity and bus speed, the contents of some MultiCAN registers
may still change if the debugger immediately reads them before the CAN node has
reached BUS IDLE or BUS OFF state, i.e. before bit SUSACK = 1_B.
2. Bit field SUMCFG in register KSCCFG for the MultiCAN module must be set to 00_B
to avoid an immediate stop (see below).
Immediately stop operation of MultiCAN module
When bit field SUMCFG in register KSCCFG for the MultiCAN module is set to 1X_B, the
clock for the MultiCAN module is switched off as soon as the suspend request from the
OCDS becomes active. As a consequence, the module immediately stops all CAN
activity (even within a running frame) and sets all transmit outputs to 1_B (recessive state).
In this state, write accesses to the module in general, and read accesses to the CAN
Errata Sheet
53
V1.7, 2014-10