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AtMega CAN Library
Well documented CAN library for AtMega processors utilizing the original Atmel driver
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This file contains the low level functions (drivers) of: More...
#include "can_drv.h"Functions | |
| void | can_clear_all_mob (void) |
| uint8_t | can_get_mob_free (void) |
| uint8_t | can_get_mob_status (void) |
| void | can_get_data (uint8_t *p_can_message_data) |
| uint8_t | can_auto_baudrate (uint8_t mode) |
| uint8_t | can_fixed_baudrate (uint8_t mode) |
This file contains the low level functions (drivers) of:
Copyright (c) 2007 Atmel.
Use of this program is subject to Atmel's End User License Agreement. Please read file license.txt for copyright notice.
- CAN (Controller Array Network)
- for AT90CAN128/64/32
This file can be parsed by Doxygen for automatic documentation generation. This file has been validated with AVRStudio-413528/WinAVR-20070122.
| uint8_t can_auto_baudrate | ( | uint8_t | mode | ) |
This function programs itself the CANBTx registers if there is some communication (activity) on the CAN bus.
| Evaluation | needed ==0: start the evaluation from faster baudrate ==1: (re)start an evaluation with CANBTx registers contents |
Temporary variable
Bit timing segment variables
Computing needed
Keys for "while()" loops
Key for configurate CAN
Timer overflow count
Count of bit timing configuration tried
Return flag
— Default setting
— Init segment variables with MIN values if mode=0 or init segment variables with CANBTx if mode=1
Try this configuration
Enable "while (wait_for_rx ..." loop
mode = 1
To enter in "while (evaluate ..." loop
Look for the next configuration
Skip "while (wait_for_rx ..." loop
— Clear all MOb's (CANMSG not cleared)
Page index
All MOb Registers = 0x00
— CANBTx registers update (sjw = phs2/2, 3 sample points)
— Set CAN-Timer - Used for time-out There are 641 (0x281) possible evaluations. The first one provides the faster the faster bit timing, the last one gives the slower. It is necessary to modulate the time-out versus bit timing (0x281>>3=0x50, matching an U8).
— MOb configuration
Use MOb-0
Reset MOb status (undone by "Can_reset()")
MOb 0 in receive mode
CAN controller configuration
Enable CAN controller in "listen" mode
Wait for Enable OK
Reset General errors and OVRTIM flag
Try to perform a CAN message reception in "LISTEN" mode without error and before a time_out done by CAN-Timer. Else gives the hand to "EVALUATE LOOP" to have a new set of bit timing.
— RxOK received ?
— It is the successful output of "can_auto_baudrate" function
Out of "while (wait_for_rx ..." loop
Will skip "while (evaluate ..." loop
Out of "while (bt_not_found ..." loop
Return flag = TRUE
Disable MOb-0
Disable CAN controller & reset "listen" mode
Wait for Disable OK
— Else stop if any errors
— MOb error ?
Will enter in "while (evaluate ..." loop
Out of "while (wait_for_rx ..." loop
— Time_out reached ?
— First Time_out
— Second Time_out
Will enter in "while (evaluate ..." loop
Out of "while (wait_for_rx ..." loop
— General error ?
Will enter in "while (evaluate ..." loop
Out of "while (wait_for_rx ..." loop
Try this configuration
Compute a new bit timing configuration. First, Phase 1 is increased, then Phase2=Phase1 and if Phase1>5, Phase1 can be equal to Phase2 or Phase2+1. After this, the number of TQ is increased up to its high limit and after it is the Prescaler. During the computing high (80%) and low (75%) limits of sampling point location are tested. SJW and the number of sampling points are not calculated in this loop.
— It is the failing of "can_auto_baudrate" function
Out of "while (evaluate ..." loop
Return flag = FALSE
Out of "while (bt_not_found ..." loop
Disable MOb-0
Disable CAN controller & reset "listen" mode
Wait for Disable OK
— If psh1 > 5 then phs1 =phs2 or =phs2+1, else phs1=phs2
— Test PRS limits
— Values accepted if 80% >= sampling point >= 75%
Out of "while (evaluate ..." loop &
new "while (bt_not_found ..." loop
| void can_clear_all_mob | ( | void | ) |
This function clears the Mailbox content. It reset CANSTMOB, CANCDMOB, CANIDTx & CANIDMx and clears data FIFO of MOb[0] upto MOb[LAST_MOB_NB].
| none |
Page index
All MOb Registers=0
| uint8_t can_fixed_baudrate | ( | uint8_t | mode | ) |
This function programs the CANBTx registers with the predefined values CONF_CANBT1, CONF_CANBT2, CONF_CANBT3.
| (unused!) |
| void can_get_data | ( | uint8_t * | p_can_message_data | ) |
This function copy the data from the selected MOb to the address passed as parameter.
| CAN | message data address. |
| uint8_t can_get_mob_free | ( | void | ) |
This function returns the number of the first MOb available or 0xFF if no MOb is available.
| none. |
Disable configuration
| uint8_t can_get_mob_status | ( | void | ) |
This function returns information "MOB completed its job" if one of the RXOK or TXOK Flag is set or "MOB not completed its job if no RXOK and TXOK flags are set. Previously, this function checks if the MOb is configured or not and in case of the MOB not configured, the function returns "MOB_DISABLE".
| none. |
1.8.13