Hello,
I’m in charge of the porting of an application which communicates with a
FTDI_SIO and a FT232BM.
The vendor:product is: 0403:6001
The windows version of this software uses the FTDI serial driver at the
input transfer rate is about 270 Ko/s.
When porting the code under linux, I first try to use libusb 0.1.7. I
was surprised to see that the usb_read_bulk parameters differ depending
on the linux distribution! I first tune the timeout and buffer size
parameter for the dev. platform (Red Hat 8 and Red Hat 9). The transfer
rate is about 130 Ko/s. The same code is not running with other Linux
distributions:
SuSE Linux 8.1 (i386) distribution with a 2.4.19 Kernel
SuSE Linux 8.2 (i586) distribution with 2.4.20 Kernel
I had to change the buffer size to 64 Kb as well as the timer. The
maximum rate reached on these system are about 35 Ko/s.
After that, I tried to use the FTDI_SIO module and worked with the
ttyUSBx serial port. The basic open. Close, read, write command work
perfectly. But the input transfer rate is really bad: 10 Ko/s.
When I try to use advanced serial configuration (set a different
baudrate or any kind of options), there is absolutely no difference in
performance.
Can anybody tell me either
- How to configure usb_read_bulk for an optimal transfer rate
- How to configure the FTDI_SIO for better performances
Thank you in advance
-- Gaëtan
Copy of the lsusb command:
...
Bus 001 Device 006: ID 0403:6001 Future Technology Devices
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 0 Interface
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 8
idVendor 0x0403 Future Technology Devices
idProduct 0x6001
bcdDevice 4.00
iManufacturer 1 VRAI
iProduct 2 easyTrack v1.0
iSerial 3 ET_v0100
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 32
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0xc0
Self Powered
MaxPower 0mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 2
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 255 Vendor Specific Subclass
bInterfaceProtocol 255 Vendor Specific Protocol
iInterface 2 easyTrack v1.0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 2
Transfer Type Bulk
Synch Type none
wMaxPacketSize 64
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x02 EP 2 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type none
wMaxPacketSize 64
bInterval 0
Language IDs: (length=4)
0409 English(US)
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