Reading From The Device Via Rs232; Pxi Express; Setting Up The Pci To Serial Bridge - SIGNALCORE SC5312A User Manual

6 SC5312A & SC5313A Hardware Manual
transmission will cause the device to behave erratically or hang. Information for writing to the
configuration registers is provided in Table 3. Configuration Registers. Upon the execution of the register
that was sent, the device will return one (1) byte of data with bit 1 high to indicate success. This byte
must be read by the host to clear its receive buffer so that reading subsequent registers will not contain
corrupted data. Furthermore, reading back this byte will ensure that the device is ready for the next
register command.

Reading from the Device Via RS232

To query information from the device, the query registers are addressed, and data is returned. Table 4.
Query Registers contains the query register information. As with the configuration registers, it is
important that all data byte(s) (write) associated with the query registers are sent even if they are null. All
queries will return 8 bytes of data (read) with the first received byte being the most significant (MSB).
Section 4.2 Query Registers provides the format details of the received data.

PXI Express

The PXIe interface contains a high-speed PCIe-to-Serial bridge chip. This bridge chip communicates with
the onboard microcontroller serially. The interface on the bridge chip resides at offset addresses between
0x00 and 0xFF from BAR0; which is memory mapped. A kernel level driver for the operating system is
needed to access this memory address. A simple driver using IO controls should be sufficient to read and
write byte data to this block of addresses. Although SignalCore provides the driver and API for these
products, information is provided here for users who may need to write drivers for a different operating
system or a different driver. An example would be writing the API for the Linux operating system.

Setting Up the PCI to Serial Bridge

The serial function of the bridge chip must first be initialized before it can communicate with the onboard
microcontroller, and hence communication between the microcontroller and the PXIe bus. The
initialization can be done at the kernel level mode or at the user level mode, the decision is left to the
user. The following table lists the programming order of the bridge register addresses to initialize and
setup the serial port function.
Rev 2.1 | SC5312A & SC5313A
Step BAR0 Register
Address
1 0x10CC
2 0x1004
3 0x10C2
4 0x10C1
5 0x10C3
6 0x1003
7 0x1000
8 0x1001
9 0x1003
10 0x1002
User Manual
Data
(Byte)
0x00
0x80
0x04
0x00
0x01
0x80
0x10
0x00
0x03
0x07
SignalCore, Inc.