LIN-compatible fast-data bus
Methods and transceivers are provided for enabling fast-data messages on a local interconnect network (LIN) compatible bus. One illustrative slave transceiver embodiment includes: a comparator and a digital-to-analog converter (DAC). The comparator detects amplitude modulation of a bias voltage at a first baud rate on a serial bus line to receive a first LIN frame header having a frame identifier for a fast-data frame. The DAC responsively drives a fast-data response message having an expanded payload and/or a higher baud rate on the serial bus line.
1. An extended local interconnect network (LIN) bus communication method for a slave LIN bus transceiver, the method comprising:
receiving a first LIN frame header at a first baud rate on a serial bus line, the first LIN frame header having a frame identifier for a fast-data frame; and
sending a fast-data response message at a second baud rate on the serial bus line, the second baud rate being larger than the first baud rate.
2. The method of claim 1 , further comprising:
receiving a second LIN frame header on the serial bus line, the second LIN frame header having a frame identifier for a standard LIN frame; and
sending a standard LIN response message at the first baud rate on the serial bus line, the standard LIN response message having at most eight data bytes and a one-byte checksum.
3. The method of claim 2 , wherein the fast-data response message has more than eight data bytes.
4. The method of claim 3 , wherein each data byte of the fast-data response message and of the standard LIN response message is preceded by a start bit and followed by a stop bit.
5. The method of claim 3 , wherein the fast-data response message has at least twenty data bytes.
6. The method of claim 1 , wherein said sending includes using pulse shaping to limit spectral energy above the second baud rate.
7. The method of claim 6 , wherein the pulse shaping is sinusoidal pulse shaping.
8. The method of claim 7 , wherein the first LIN frame header has a characteristic spectrum that, at any frequency above the second baud rate, exceeds or approximately equals the spectral energy of the fast-data response message.
9. The method of claim 1 , wherein the first baud rate is 20 kHz and the second baud rate is at least 40 kHz.
10. An extended LIN bus communication method for a master LIN bus transceiver, the method comprising:
sending a first LIN frame header at a first baud rate on a serial bus line, the first LIN frame header having a frame identifier for a fast-data frame; and
receiving a fast-data response message at a second baud rate on the serial bus line, the second baud rate being larger than the first baud rate.
11. The method of claim 10 , wherein said sending includes setting a universal asynchronous receiver/transmitter (UART) to the first baud rate, and wherein said receiving includes setting the UART to the second baud rate.
12. The method of claim 10 , further comprising:
sending a second LIN frame header on the serial bus line, the second LIN frame header having a frame identifier for a standard LIN frame; and
receiving a standard LIN response message at the first baud rate on the serial bus line, the standard LIN response message having at most eight data bytes and a one-byte checksum.
13. The method of claim 12 , wherein the fast-data response message has more than eight data bytes.
14. The method of claim 13 , wherein each data byte of the fast-data response message and of the standard LIN response message is preceded by a start bit and followed by a stop bit.
15. The method of claim 10 , wherein the first baud rate is 20 kHz and the second baud rate is at least 40 kHz.
16. A slave LIN bus transceiver that comprises:
a comparator that detects amplitude modulation of a bias voltage at a first baud rate on a serial bus line to receive a first LIN frame header having a frame identifier for a fast-data frame; and
a digital-to-analog converter (DAC) that responsively drives a fast-data response message having more than eight data bytes.
17. The transceiver of claim 16 , wherein the DAC drives the fast-data response message at a second baud rate on the serial bus line, the second baud rate being larger than the first baud rate.
18. The transceiver of claim 17 , wherein the DAC applies pulse shaping to bits of the fast-data response message to limit spectral energy above the second baud rate.
19. The transceiver of claim 17 , wherein the comparator receives a second LIN frame header on the serial bus line, the second LIN frame header having a frame identifier for a standard LIN frame, and wherein the DAC responsively drives a standard LIN response message at the first baud rate on the serial bus line, the standard LIN response message having at most eight data bytes and a one-byte checksum.
20. The transceiver of claim 16 , wherein each data byte of the fast-data response message and of the standard LIN response message is preceded by a start bit and followed by a stop bit.