ST ST10F276E - CAN Modules; Memory and Pin Mapping; CAN1 Mapping; CAN2 Mapping

CAN modules UM0404
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21 CAN modules
The two integrated CAN modules (CAN1 and CAN2) are identical and handle the
completely autonomous transmission and reception of CAN frames in accordance with the
CAN specification V2.0 part A and B (active).
The module is based on C-CAN module characteristics. The following system resources are
used to interface the module with the ST10 core:
• Interrupt of CAN1 and CAN2 are connected to the XBUS interrupt lines: refer to next
Section 21.2: Interrupt for details.
• Both CAN modules have to be selected, before the bit XPEN is set in SYSCON
register, by setting the proper bit in XPERCON register.
• After reset, CAN1 is enabled by default (see Reset value of XPERCON register). The
CAN2 on the contrary is not enabled.
21.1 Memory and pin mapping
21.1.1 CAN1 mapping
Address range 00’EF00h - 00’EFFFh is reserved for the CAN1 Module access. The CAN1 is
enabled by setting bit XPEN of the SYSCON register and bit 0 of XPERCON register.
Accesses to the CAN Module use demultiplexed addresses and a 16-bit data bus (only word
accesses are possible). Two waitstates give an access time of 62.5ns @64MHz CPU clock.
No tristate waitstate is used.
After reset, CAN1 is enabled by default (see Reset value of XPERCON register). It is
available on pins P4.5 and P4.6.
21.1.2 CAN2 mapping
Address range 00’EE00h - 00’EEFFh is reserved for the CAN2 Module access. The CAN2
is enabled by setting bit XPEN of the SYSCON register and bit 1 of the XPERCON register.
Accesses to the CAN Module use demultiplexed addresses and a 16-bit data bus (only word
accesses are possible). Two waitstates give an access time of 62.5ns @64MHz CPU clock.
No tristate waitstate is used.
After reset, CAN2 is disabled by default (see Reset value of XPERCON register). Once
enabled, it is available on pins P4.4 and P4.7. When I
2
C interface is enabled as well (bit
XI2CEN in XPERCON register), CAN2 is not available on P4.4 and P4.7, since for I
2
C a
higher priority has been set by hardware option.
Note: If one or the two CAN modules are used, Port4 cannot be programmed to output all eight
segment address lines. Thus, only four segment address lines can be used, reducing the
external memory space to 5 Mbytes (1 Mbyte per CS
line).
21.1.3 Register summary
In the tables below, the CAN modules register mapping is summarized.