Is there any requirement for the length of the data packet of the serial port? For example, ACK 00 00 means that the data has been received, instead of...

QWE4562009

Is there any requirement for the length of the data packet of the serial port? For example, ACK 00 00 means that the data has been received, instead of... [Copy link]

Is there any requirement for the length of the data packet of the serial port? For example, ACK 00 00 means that the data has been received, rather than a long string of numbers.

maychang

Whether to use a specific character to indicate the end of a packet is up to you. You can set it up as you like.

chunyang

The serial port itself is only related to the frame length, which is composed of 10 or 11 bits of data, that is, a byte. Multi-byte data has nothing to do with the serial port and is completely self-defined. You have to check the protocol to see if there is any requirement for the packet length.

QWE4562009

chunyang posted on 2019-12-11 16:29 The serial port itself is only related to the frame length, which is composed of 10 or 11 bits of data, that is, forming a byte. Multi-byte data has nothing to do with the serial port and is completely self-determined...

55 Is such a group a byte?

maychang

QWE4562009 posted on 2019-12-11 16:43 55 Is such a group a byte?

"Is a group of 55 a byte?"

You need to first clarify what "55" is. If it is a hexadecimal number, it is indeed one byte. If it is an ASCII code, it is two bytes.

chunyang

QWE4562009 posted on 2019-12-11 16:43 55 Is such a group a byte?

The first floor diagram should be in hexadecimal. In hexadecimal, 0x55 is a byte. Note that to avoid confusion, hexadecimal numbers should be written as 0x55 or 55H. If you give 55 directly, it will become ASCII code in principle.

QWE4562009

maychang posted on 2019-12-11 16:59 "Is a group of 55 a byte?" You must first clarify what "55" is. If it is hexadecimal...

Does a frame in a microcontroller refer to multiple bytes?

QWE4562009

chunyang posted on 2019-12-12 10:48 The first floor picture should be in hexadecimal. In hexadecimal, 0x55 is one byte. Note that to avoid confusion, the hexadecimal number should be written as 0x55 in the text...

This is a hexadecimal number.

maychang

QWE4562009 posted on 2019-12-12 15:44 Does a frame in a microcontroller refer to multiple bytes?

"A frame in a microcontroller refers to multiple bytes, right?"

A "frame" of the microcontroller serial port is a byte (8 bits) plus a start bit, an end bit (and possibly a check bit).

QWE4562009

maychang published on 2019-12-12 15:53 "A frame in a microcontroller refers to multiple bytes, right?" A "frame" of a microcontroller serial port is a byte (8 bits) ...

The length of a frame is not fixed.

maychang

QWE4562009 posted on 2019-12-13 16:12 The length of that frame is not fixed

The length of a frame sent by the serial port is not fixed. It may be 10 bits, 10.5 bits, 11 bits... But the different lengths are not much different. They will not be shorter than 10 bits, nor longer than 13 bits.