• AVR Freaks

MCP2200 VCP doesn't work

Page: < 12 Showing page 2 of 2
Author
mkm
New Member
  • Total Posts : 16
  • Reward points : 0
  • Joined: 2011/03/07 03:13:01
  • Location: 0
  • Status: offline
Re:MCP2200 VCP doesn't work 2011/03/08 08:17:52 (permalink)
0
The RTS pin on the MCP2200 works fine being controlled by ... a Linux host. Indeed, there's an issue in the Windows supplied usbser.sys driver and this is the cause for RTS control inability. I've tried toggling the RTS pin from Realterm on XP and Win 7 machines. The Microsoft CDC driver still has issues. When I tried to toggle the DTR pin I could see the USB packet being sent (SET_CONTROL_LINE_STATE), but since there's no DTR on the MCP2200 there was no change on the pins. But when I tried to toggle the RTS pin, no USB packet (SET_CONTROL_LINE_STATE) packet was sent.

This made me wonder how it works under Linux. I've used the readme file from the MCP2200's page and I set up the driver. Then, I started gtkterm and from the menu (or by pressing F8) I was able to perfectly control the RTS. Smile Bingo, the RTS can be controlled from the host side.

So, it seems when the Microsoft will have their driver fixed (maybe not in ages) the RTS on the MCP2200 will be controlled from Windows as well.

Mark
#21
chinzei
Super Member
  • Total Posts : 2250
  • Reward points : 0
  • Joined: 2003/11/07 12:39:02
  • Location: Tokyo, Japan
  • Status: offline
Re:MCP2200 VCP doesn't work 2011/03/08 12:12:06 (permalink)
0

For a workaround of RTS issue of Windows usbser.sys,

Put RTS and then DTR (or both RTS and DTR simultaneously).
RTS signaling is sent at the timing when DTR is put, over single SET_CONTROL_LINE_STATE request.

You don't need to toggle DTR. Any value (0/1) will do, regardless of former DTR status.

Tsuneo
#22
vinayk
New Member
  • Total Posts : 4
  • Reward points : 0
  • Joined: 2018/06/11 22:35:10
  • Location: 0
  • Status: offline
Re:MCP2200 VCP doesn't work 2018/06/13 22:58:14 (permalink)
0
I am having same type of issue. Need to toggle the RTS PIN to high or low.
 
I have implemented the USB serial connection using the PIC32MX795F512L. I want to implement USB to Serial to RS485 connection using MCP2200 breakout module and Sparkfun RS485 breakout module. I have checked both TX and RX from MCP2200 to RS485 by manually toggle the RTS pin of RS485 module, its working. Now I need to toggle the RTS pin automatically from MCP2200, is there any way to toggle the RTS PIN?
#23
Page: < 12 Showing page 2 of 2
Jump to:
© 2020 APG vNext Commercial Version 4.5