> > Does someone implement "auto flow control on 16550a (with enable AFE bit)"
 > > to com.c?
 > 
 > Is this feature supported by all 16550's?

 Sorry, I don't know. TI's 16550a (TL16550C) have this feature.
I don't know another 16550 (for example, I have GoldStar's 16550!)
have this.


 > How does one enable it?

AFE bit is located in MCR register.

*** comreg.h.org	Tue Feb  6 21:58:06 1996
--- comreg.h	Wed Apr  3 03:05:52 1996
***************
*** 82,87 ****
--- 82,88 ----
  #define	LCR_5BITS	0x00	/* 5 bits */
  
  /* modem control register */
+ #define	MCR_AFE		0x20	/* Auto Flow Enable */
  #define	MCR_LOOPBACK	0x10	/* Loop test: echos from TX to RX */
  #define	MCR_IENABLE	0x08	/* Out2: enables UART interrupts */
  #define	MCR_DRS		0x04	/* Out1: resets some internal modems */


TL 16550's databook shows as follows:

	| MCR_AFE | MCR_RTS |
	+---------+---------+--------------------------------
	|    1    |    0    | auto /RTS and auto /CTS enable
	|         |         | (auto flow control enable)
	+---------+---------+--------------------------------
	|    1    |    0    | enable auto /CTS only
	+---------+---------+--------------------------------
	|    0    |    X    | disable auto /RTS and auto /CTS
	+---------+---------+--------------------------------






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					msaitoh@spa.is.uec.ac.jp