Intel 8XC196NT, 87C196CB user manual Canmsg xCON0, Msgval, Bit, Txie

87C196CB SUPPLEMENT

CAN_MSGxCON0	Address:	1Ex0H (x = 1–F)
x = 1–15 (87C196CB)	Reset State:	Unchanged

Program the CAN message object x control 0 (CAN_MSGxCON0) register to indicate whether the message object is ready to transmit and to control whether a successful transmission or reception generates an interrupt. The least-significant bit-pair indicates whether an interrupt is pending.

This register consists of four bit-pairs — the most-significant bit of each pair is in true form and the least-significant bit is in complement form. This format allows software to set or clear any bit with a single write operation, without affecting the remaining bits.

87C196CB

7

MSGVAL MSGVAL TXIE TXIE

0

RXIE RXIE INT_PND INT_PND

Bit	Bit			Function
Number	Mnemonic
7:6	MSGVAL	Message Object Valid
		Set this bit-pair to indicate that a message object is valid (configured and
		ready for transmission or reception).
		bit 7	bit 6
		0	1	not ready
		1	0	message object is valid
		The CAN peripheral will access a message object only if this bit-pair
		indicates that the message is valid. If multiple message objects have the
		same identifier, only one can be valid at any given time.
		During initialization, software should clear this bit for any unused message
		objects. Software can clear this bit if a message is no longer needed or if
		you need to change a message object’s contents or identifier.
5:4	TXIE	Transmit Interrupt Enable
		Receive message objects do not use this bit-pair.
		For transmit message objects, set this bit-pair to enable the CAN
		peripheral to initiate a transmit (TX) interrupt after a successful trans-
		mission. You must also set the interrupt enable bit (CAN_CON.1) to enable
		the interrupt.
		bit 5	bit 4
		0	1	no interrupt
		1	0	generate an interrupt

Figure 7-14. CAN Message Object x Control 0 (CAN_MSGxCON0) Register

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