Espressif ESP32 Technical Reference Manual page 564

21 Two-wire Automotive Interface (TWAI)
21.5.6.1 Single Filter Mode
Single Filter Mode is enabled by setting the
mask values to define a single filter. The single filter can filter the following bits of a Data or Remote Frame:
• SFF
– The entire 11-bit ID
– RTR bit
– Data byte 1 and Data byte 2
• EFF
– The entire 29-bit ID
– RTR bit
The following Figure 21-8
Mode.
21.5.6.2 Dual FIlter Mode
Dual Filter Mode is enabled by setting the
mask values to define a two separate filters, referred to as filter 1 or two. Under Dual Filter Mode, a message will
be accepted if it is accepted by one of the two filters.
The two filters can filter the following bits of a Data or Remote Frame:
• SFF
– The entire 11-bit ID
– RTR bit
– Data byte 1 (for filter 1 only)
• EFF
Espressif Systems
TWAI_RX_FILTER_MODE
illustrates how the 32-bit code and mask values will be interpreted under Single Filter
Figure 21-8. Single Filter Mode
TWAI_RX_FILTER_MODE
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bit to 1. This will cause the 32-bit code and
bit to 0. This will cause the 32-bit code and
564 ESP32 TRM (Version 5.2)