Basic Read/Write Command Explanations; Read Command - Basler A400K User Manual

Configuring the Camera

4.3.2 Basic Read/Write Command Explanations

4.3.2.1 Read Command

This section includes a text description the hex digits included in a command message used to
read the Status field of the Test Image Mode CSR (see page 4-32). The intent of this section is to
give you a basic understanding of the elements included in a read command. Section
actual samples of the code used to send a read command.
The hex digits included in the read command are:
0x01, 0x0C, 0x01, 0x00, 0x18, 0x01, 0x15, 0x03
is the BFS field.
0x01
The value in the BFS field is always 0x01.
is the FTF field.
0x0C
The hex value of 0x0C in the FTF field converts to a binary value of 0b00001100.
Bits 7 through 3 of the binary value indicate the OpCode. As shown in the table on page
4-47, an OpCode value of 0b00001 indicates that this is a read command frame.
Bit 2 indicates the presence or absence of a BCC in the frame. As shown in the table on
page 4-47, when this bit is set to 0b1, it indicates that a BCC is present.
Bits 1 and 0 indicate the AddrLen. As shown in the table on page 4-47, a value of 0b00
for the AddrLen indicates that the address portion of this frame contains a 16-bit address.
If you check the table on page 4-32, you will find that the address for the Status field of
the Test Image CSR is 0x1800, a 16-bit address. (You are free to use any supported
AddrLen as long as the CSR address will fit into it.)
is the DataLen field.
0x01
This field indicates the data size in bytes that will be transferred by using this read
command. As shown in the table on page 4-32, the data size for the Status field of the
Test Image CSR is 1 byte.
(Note that for read commands, the data size specified in the DataLen field represents the
number of bytes of data that you expect to see in the response frame. No data bytes are
actually included in the read command.)
0x00, 0x18
This field indicates the CSR address from which the data bytes will be read.
The little endian values of 0x00, 0x18 in the address field translate to an address of
0x1800. If you check the table on page 4-32, you will find that 0x1800 is the address for
the Status field of the Test Image CSR.
is the BCC field.
0x15
See page
(Note that the use of a BCC is optional. In this example, we assume that a BCC is used.)
is the BFE.
0x03
The value in the BFE field is always 0x03 .
4-50
DRAFT
is the Address field (in little endian).
4-52 for instructions on calculating a BCC.
4.4 includes
Basler A400k