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author | Gregory Nutt <gnutt@nuttx.org> | 2013-10-23 11:32:12 -0600 |
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committer | Gregory Nutt <gnutt@nuttx.org> | 2013-10-23 11:32:12 -0600 |
commit | 4d2c732d746cd8a3624886fbc83e0d31d5ca10f3 (patch) | |
tree | 190148929f005e63dc9d45d8e4c4a1ffedc797dc /nuttx/configs/sama5d3x-ek | |
parent | a509293e4d1bb6c516c0788f4fde43c7b250c2db (diff) | |
download | px4-nuttx-4d2c732d746cd8a3624886fbc83e0d31d5ca10f3.tar.gz px4-nuttx-4d2c732d746cd8a3624886fbc83e0d31d5ca10f3.tar.bz2 px4-nuttx-4d2c732d746cd8a3624886fbc83e0d31d5ca10f3.zip |
SAMA5 CAN: Update readme on how to configure CAN
Diffstat (limited to 'nuttx/configs/sama5d3x-ek')
-rw-r--r-- | nuttx/configs/sama5d3x-ek/README.txt | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/nuttx/configs/sama5d3x-ek/README.txt b/nuttx/configs/sama5d3x-ek/README.txt index 2a6b52208..6199e2c5d 100644 --- a/nuttx/configs/sama5d3x-ek/README.txt +++ b/nuttx/configs/sama5d3x-ek/README.txt @@ -77,6 +77,7 @@ Contents - HSMCI Card Slots - USB Ports - AT24 Serial EEPROM + - CAN Usage - SAMA5D3x-EK Configuration Options - Configurations @@ -652,6 +653,85 @@ AT24 Serial EEPROM By default, PA30 and PA31 are SWJ-DP pins, it can be used as a pin for TWI peripheral in the end application. +CAN Usage +========= + + CAN Configuration + ----------------- + + The following steps illustrate how to enable CAN0 and/or CAN1 in the NuttX + configuration: + + System Type -> SAMA5 Peripheral Support + CONFIG_SAMA5_CAN0=y : Select CAN0 and/or CAN1 + CONFIG_SAMA5_CAN1=y + + Device Drivers -> CAN Driver Support + CONFIG_CAN=y : (Automatically selected) + CONFIG_CAN_EXTID=y : For extended, 29-bit CAN IDs + + System Type -> CAN Drive Support + CONFIG_SAMA5_CAN0_BAUD=250000 : Select some BAUD for CAN0 (if enabled) + CONFIG_SAMA5_CAN0_NRECVMB=1 : Select number of receive mailboxes (see below) + CONFIG_SAMA5_CAN1_BAUD=250000 : Select some BAUD for CAN1 (if enabled) + CONFIG_SAMA5_CAN1_NRECVMB=1 : Select number of receive mailboxes (see below) + + Receive Mailboxes and Address Filtering + --------------------------------------- + + The SAMA5 CAN0 peripheral supports 8 mailboxes that can be used for sending + and receiving messages. Note that the number of dedicated receive mailboxes + (CONFIG_SAMA5_CANn_NRECVMB) was set to one in the above configuration. This + could be set to any value from 1 to 3 (the upper limit of 3 is purely + arbrary and can be increased with some minor code enhancement). The + remainder can be configured dynamically to send CAN messages. + + Why would you want to use more than one receive mailbox? There are two + reasons. Multiple receive mailboxes might needed to either (1) receive + bursts of messages, or (2) to support multiple groups of messages filtered + on message ID. + + You must also specify the address filtering for each dedicated receive mailbox: + + System Type -> CAN Drive Support + CONFIG_SAMA5_CAN0_ADDR0 and CONFIG_SAMA5_CAN0_MASK0 : If CONFIG_SAMA5_CAN0_NRECVMB >= 1 + CONFIG_SAMA5_CAN0_ADDR1 and CONFIG_SAMA5_CAN0_MASK1 : If CONFIG_SAMA5_CAN0_NRECVMB >= 2 + CONFIG_SAMA5_CAN0_ADDR2 and CONFIG_SAMA5_CAN0_MASK2 : If CONFIG_SAMA5_CAN0_NRECVMB >= 3 + CONFIG_SAMA5_CAN1_ADDR0 and CONFIG_SAMA5_CAN1_MASK0 : If CONFIG_SAMA5_CAN1_NRECVMB >= 1 + CONFIG_SAMA5_CAN1_ADDR1 and CONFIG_SAMA5_CAN1_MASK1 : If CONFIG_SAMA5_CAN1_NRECVMB >= 2 + CONFIG_SAMA5_CAN1_ADDR2 and CONFIG_SAMA5_CAN1_MASK2 : If CONFIG_SAMA5_CAN1_NRECVMB >= 3 + + Only messages that have IDs that match the CONFIG_SAMA5_CANn_ADDRn when both + the received and the configured address are masked by CONFIG_SAMA5_CANn_MASKn + will be accepted. For eacmple, if the mask is all ones, then only messasges + with exact address matches will be accepted; if the mask is all zeroes than + any address will be accepted. + + CAN connectors + -------------- + + CAN1 and CAN2 are available via RJ-11 connectors on the SAMA5Dx-EK. Each + is wired as follows. Also shown below is the matching pins if you want connect + the CAN to a device that uses an DB-9 connector. Both connector types are + common. + + +----------+ RJ-11 DB-9 + | O | ----------- -------------- + +------------+ | | Pin 1 3v3 Pin 1 N/C + | +--+ | | o5 | Pin 2 5v Pin 2 CANL + | | | | | o9 | Pin 3 N/C Pin 3 GND + | +-+ +-+ | | o4 | Pin 4 CANL Pin 4 N/C + | | | | | o8 | Pin 5 CANH Pin 5 N/C + | |654321| | | o3 | Pin 6 N/C Pin 6 N/C + | |oooooo| | | o7 | Pin 7 CANH + | +------+ | | o2 | Pin 8 N/C + +------------+ | o6 | Pin 9 N/C + RJ-11 Female | x1 | + | | + | O | + +----------+ + DB-9 Male + SAMA5D3x-EK Configuration Options ================================= |