T89C51CC02 Atmel, T89C51CC02 Datasheet - Page 78

• Manufacturer Part Number: T89C51CC02
• Description: 8-Bit MCU
• Manufacturer: Atmel

T89C51CC02
15.9. Time Trigger Communication (TTC) and Message Stamping
The T89C51CC02 has a programmable 16-bit Timer (CANTIMH&CANTIML) for message stamp and TTC.
This CAN Timer starts after the CAN controller is enabled by the ENA bit in the CANGCON register.
Two user modes of the timer are implemented:
The CAN Timer works in a loopback mode (0x0000... 0xFFFF, 0x0000) which serves as a time base to stamp all
received or transmitted messages.
When the timer overflows from 0xFFFF to 0x0000, an interrupt is generated if the ETIM bit of the CAN Timer
in a micro-controller interrupt system register is set.
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Time Trigger Communication:
Catch of this timer in the CANTTCH & CANTTCL registers on SOF or EOF, depending on the SYNCTTC
bit in the CANGCON register, when the network is configured in TTC by the TTC bit in the CANGCON register.
In this mode, CAN only sends the frame once, even if an error occurs.
Message Stamping
Catch of this timer in the CANSTMPH & CANSTMPL registers of the message object which received or sent
the frame.
All messages can be stamps.
The stamping of a received frame occurs when the RxOk flag is set.
The stamping of a sent frame occurs when the TxOk flag is set.
CLOCK
CANSTCH.4
CANSTCH.5
Fcan
RXOK i
TXOK i
CANSTMPH & CANSTMPL
6
CANTCON
CANTIMH & CANTIML
Figure 63. Block diagram of CAN Timer
Preliminary
CANGCON.1
CANTTCH & CANTTCL
ENA
When 0xFFFF to 0x0000
CANGCON.5
TTC
SYNCTTC
CANGCON.4
Rev.A - May 17, 2001
SOF on CAN frame
EOF on CAN frame
OVRTIM
CANGIT.5