SPRUJ79 November 2024 F29H850TU , F29H859TU-Q1
The MTPG triggers can be used to configure sensors or request data from synchronous mode sensors, since the MTPG can create desired pulse patterns that are recognized by the sensors. For sensors with synchronous transmit, the sensor sends data when the MTPG has sent a pulse that matches with the sensor's pulse size requirement.
The MTPG enables the operational modes laid out in Table 42-1.
| Mode | Maximum Number of Sensors Supported | Description |
|---|---|---|
| Synchronous Transmit | 1 | Sensor sends data only after receiving trigger pulse |
| Multiple Sensors on Bus | 4 | Each sensor has a specific address which the MTPG triggers in a predefined sequence. There can be a predefined broadcast sequence to configure the sensors |
| Change Mode of Operation | 1 | MTPG can change the mode of sensor operation |
Figure 42-1 shows that the MTPG consists of one signal generator and five trigger channels (Broadcast and Channels 1-4). Each channel has a set of configurations that control the signal generation, and the signal generator uses one set of configurations to generate the pulse.
On the Broadcast channel the MTPG generates a pulse and the SENT receiver does not expect data in return. There can be a predefined broadcast of sequences to configure the sensors or to change the mode of the operation. In normal mode, the SENT receiver expects data in response to a pulse, and a timeout counter acts as a check to trigger an interrupt if there is no received sync pulse within a specified time limit. The SENT channel's period register defines the length of the pulse produced by the MTPG.
The channel has ten compare registers, which toggle the signal generator output when the channel counter matches any of the compare values. The maximum number of toggles that can be created is limited by the number of compare registers.
The CMP10 compare register is unique in that this compare register controls when the receiver is enabled to sample the RX line. The SENT peripheral can only drive the output when the period of the SENT channel's counter is non-zero.
Figure 42-2 shows the interaction between the output control, RX line, and the compare registers. To generate one trigger pulse, two compare registers must be non-zero. This is because the compare registers are triggered in sequence, so for example the CMP9 register must be larger than CMP8, which must be larger than CMP7, and so on. The purpose of this is to reduce the logic and length of the critical path. The respective Sn_MTP_CMP10RE register (where n is 1 through 4) is only used if the receiver input gating needs to occur earlier than the period time. The MTPG counter uses clock tick units.
The signal generator initializes a counter to 0x0 after receiving a request from a channel to start the pulse sequence, and counts to the value stored in the channel's respective period register.