UM10503
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1.3 — 6 July 2012
1092 of 1269
NXP Semiconductors
UM10503
Chapter 42: LPC43xx C_CAN
42.6.4 CAN timing register
42.6.4.1 CAN clock divider register
This register determines the CAN clock signal. The CAN_CLK is derived from the
peripheral clock PCLK divided by the values in this register.
42.7 Functional description
42.7.1 C_CAN controller state after reset
After a hardware reset, the registers hold the values described in
. Additionally,
the busoff state is reset and the output CAN_TX is set to recessive (HIGH). The value
0x0001 (INIT = ‘1’) in the CAN Control Register enables the software initialization. The
CAN controller does not communicate with the CAN bus until the CPU resets INIT to ‘0’.
The data stored in the message RAM is not affected by a hardware reset. After power-on,
the contents of the message RAM is undefined.
Table 973. CAN message valid 2 register (MSGV2, address 0x400E 2164 (C_CAN0) and
0x400A 4164 (C_CAN1)) bit description
Bit
Symbol
Description
Access
Reset
value
15:0
MSGVAL32_17
Message valid bits of message objects 32 to 17.
0 = This message object is ignored by the message
handler.
1 = This message object is configured and should
be considered by the message handler.
R
0x00
31:16 -
Reserved
-
-
Table 974. CAN clock divider register (CLKDIV, address 0x400E 2180 (C_CAN0) and 0x400A
4180 (C_CAN1)) bit description
Bit
Symbol
Description
Reset
value
Access
3:0
CLKDIVVAL Clock divider value
CAN_CLK = PCLK/(2
CLKDIVVAL -1
+1)
0000: CAN_CLK = PCLK divided by 1.
0001: CAN_CLK = PCLK divided by 2.
0010: CAN_CLK = PCLK divided by 3.
0010: CAN_CLK = PCLK divided by 4.
0011: CAN_CLK = PCLK divided by 5.
0100: CAN_CLK = PCLK divided by 9.
0101: CAN_CLK = PCLK divided by 17.
...
1111: CAN_CLK = PCLK divided by 16385.
0001
R/W
31:4
-
reserved
-
-