ST72521AR7TC View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

ST72521AR7TC

8-BIT MCU WITH NESTED INTERRUPTS, FLASH, 10-BIT ADC, FIVE TIMERS, SPI, SCI, I2C, CAN INTERFACE

STMicroelectronics 

ST72521M/R/AR

CONTROLLER AREA NETWORK (Cont’d)

10.8.4.2 Paged Registers

LAST IDENTIFIER HIGH REGISTER (LIDHR)

Read/Write

Reset Value: Undefined

7

0

LID10 LID9 LID8 LID7 LID6 LID5 LID4 LID3

LID[10:3] are the most significant 8 bits of the last

Identifier read on the CAN bus.

LAST IDENTIFIER LOW REGISTER (LIDLR)

Read/Write

Reset Value: Undefined

7

0

LDLC LDLC LDLC LDLC

LID2 LID1 LID0 LRTR 3

2

1

0

LID[2:0] are the least significant 3 bits of the last

Identifier read on the CAN bus.

LRTR is the last Remote Transmission Request bit

read on the CAN bus.

LDLC[3:0] is the last Data Length Code read on the

CAN bus.

TRANSMIT ERROR COUNTER REG. (TECR)

Read Only

Reset Value: 00h

7

0

TEC7 TEC6 TEC5 TEC4 TEC3 TEC2 TEC1 TEC0

TEC[7:0] is the least significant byte of the 9-bit

Transmit Error Counter implementing part of the

fault confinement mechanism of the CAN protocol.

In case of an error during transmission, this counter

is incremented by 8. It is decremented by 1 after

every successful transmission. When the counter

value exceeds 127, the CAN controller enters the

error passive state. When a value of 256 is reached,

the CAN controller is disconnected from the bus.

RECEIVE ERROR COUNTER REG. (RECR)

Page: 00h — Read Only

Reset Value: 00h

7

0

REC7 REC6 REC5 REC4 REC3 REC2 REC1 REC0

REC[7:0] is the Receive Error Counter implement-

ing part of the fault confinement mechanism of the

CAN protocol. In case of an error during reception,

this counter is incremented by 1 or by 8 depending

on the error condition as defined by the CAN stand-

ard. After every successful reception the counter is

decremented by 1 or reset to 120 if its value was

higher than 128. When the counter value exceeds

127, the CAN controller enters the error passive

state.

IDENTIFIER HIGH REGISTERS (IDHRx)

Read/Write

Reset Value: Undefined

7

0

ID10 ID9 ID8 ID7 ID6 ID5 ID4 ID3

ID[10:3] are the most significant 8 bits of the 11-bit

message identifier.The identifier acts as the mes-

sage’s name, used for bus access arbitration and

acceptance filtering.

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