IA82527_13 Datasheet, PDF (55/58 Pages) InnovASIC, Inc – Serial Communications Controller—CAN Protocol

IA82527
CAN Serial Communications Controller
Data Sheet
December 20, 2012
Errata No. 2
Problem: Setting the IntPnd bit to 1 from CPU interface will not cause Interrupt.
Description: During normal operation, a CAN message event sets the IntPnd bit of Control 0
Register of the appropriate message box (assuming appropriate interrupt enables are set), and the
interrupt signal is asserted. The CPU will then reset IntPnd to clear the interrupt. The errata
issue occurs if the user directly sets the IntPnd bit via the CPU interface, no interrupt will be
generated.
Workaround: None.
Errata No. 3
Problem: An unintended Remote Frame may be generated.
Description: If a Message Box is set to receive and a Remote Frame with a matching ID and
Data Length Code (DLC) is received, the IA82527 will generate an unexpected Remote Frame
for the ID in the Message Box instead of just acknowledging the CAN message.
A Message Box configured as follows may lead to this scenario, as explained below:
1. A Message Box is set with an ID in the Arbitration Registers to match the ID of Remote
Frame.
2. The Message Box Control_0 Register has MsgVal(Bits[7-6]) in the set state.
3. The Message Box Control_1 Register has all fields in the reset state.
4. The Message Box Configuration Register has the Dir bit (bit 3) reset to 0 for receive.
5. The Message Box Configuration Register has the DLC field set to match the DLC of the
Remote Frame.
When the IA82527 sees a Remote Frame that matches the Message Box ID and DLC, the
IA82527 will generate the expected RX_OK status change interrupt. The IA82527 will also
generate an unexpected RX interrupt for the Message Box that matches the ID of the Remote
Frame if the RXIE field of the Message Box Control_0 register is in the set state. In addition,
the IA82527 will generate an unexpected Remote Frame for the ID in the Message Box.
Workaround: In a system that uses remote frames, only use a single Remote Frame Requester
for a single Remote Frame Responder.
IA211080504-07
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