upd70f3402 Renesas Electronics Corporation., upd70f3402 Datasheet - Page 541

• Manufacturer Part Number: upd70f3402
• Description: 32-/16-bit Single-chip Microcontroller With Can Interface
• Manufacturer: Renesas Electronics Corporation.

(2)
(3)
(4)
Remark:
Bit error, stuff error,
form error, ACK error
CEC error
Output timing of error frame
Processing in case of error
The transmission node re-transmits the data frame or remote frame after the error frame.
(However, it does not re-transmit the frame in the single-shot mode.)
Error state
(a) Types of error states
The following three types of error states are defined by the CAN specification.
• Error active
• Error passive
• Bus-off
These types of error states are classified by the values of the TEC7 to TEC0 bits (transmission
error counter bits) and the REC6 to REC0 bits (reception error counter bits) of the CAN error coun-
ter register as shown in Table 16-13.
The present error state is indicated by the CAN module information register (CnINFO).
When each error counter value becomes equal to or greater than the error warning level (96), the
TECS0 or RECS0 bit of the CnINFO register is set to 1. In this case, the bus state must be tested
because it is considered that the bus has a serious fault. An error counter value of 128 or more
indicates an error passive state and the TECS1 or RECS1 bit of the CnINFO register is set to 1.
• If the value of the transmission error counter is greater than or equal to 256 (actually, the
• If only one node is active on the bus at start-up (i.e., when the bus is connected only to the local
transmission error counter does not indicate a value greater than or equal to 256), the bus-off
state is reached and the BOFF bit of the CnINFO register is set to 1.
station), ACK is not returned even if data is transmitted. Consequently, re-transmission of the
error frame and data is repeated. In the error passive state, however, the transmission error
counter is not incremented and the bus-off state is not reached.
n = 0, 1
Type
Error frame output is started at the timing of the bit following the detected error.
Error frame output is started at the timing of the bit following the ACK delimiter.
Table 16-12: Output Timing of Error Frame
User’s Manual U16702EE3V2UD00
Chapter 16 FCAN Controller
Output Timing
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