I'm trying to implement the sample code \stm32cube_fw_f4_v1210\STM32Cube_FW_F4_V1.21.0\Projects\STM324x9I_EVAL\Examples\CAN\CAN_Networking\Src on a STM32F429 Nucleo board. Using CubeMx. Single board for now. No transceiver and the CAN bus Tx & Rx pins not connected to a bus.
I've completed/implemented steps 1 - 5 of the CAN_Config() found in main.c of the above sample project.
To get started, I wanted to simply just transmit a message once a second and noticed the transmit mailbox gets filled after the third message. Seems like the mailboxes do not get transmitted and therefore after the third time HAL_CAN_AddTxMessage(), the three (3) mailboxes are full and HAL_CAN_AddTxMessage(0 returns an error.
What do I need to do so that the mailbox after HAL_CAN_AddTxMessage() can/will get transmitted and therefore becomes empty and available?